Wirz Research Lab - Publications

P. Crandall, V. Piccone, T. Asanuma and R. E. Wirz, “Geomagnetic Storm Risks to Air-Breathing Electric Propulsion Missions,” IEEE Aerospace Conference (2024); 10.1109/AERO58975.2024.10520952

Geomagnetic storms can cause significant and rapid increases in atmospheric density at very low Earth orbit (VLEO) altitudes potentially putting a VLEO spacecraft into an un-recoverable orbit. Air-breathing electric propulsion (ABEP) spacecraft may be more susceptible to geomagnetic storms due to the low thrust-to-drag chosen for many proposed spacecraft. For ABEP missions to become viable, risks due to geomagnetic storms must be mitigated. This work explores geomagnetic storm risks to ABEP spacecraft using an orbit propagator. Spacecraft with low ballistic coefficient and low thrust-to-drag are identified as highly susceptible to geomagnetic storm risks. Two risk mitigation strategies are investigated for these space-craft: (1) preemptive orbit raising ahead of a storm, and (2) using onboard xenon propellant to increase thruster performance during a storm. An orbit propagator is used to investigate performance of these risk mitigation strategies during a G4 (severe) geomagnetic storm in November 2004. It is shown that preemptive orbit raising successfully mitigates geomagnetic storm risks for spacecraft with higher thrust-to-drag while adding a relatively small amount of xenon propellant mitigates geomagnetic storm risk for all spacecraft.

Davis, M., Wirz, R., “Electrospray Thruster Plume Characterization via Physics-Informed Machine Learning,” AIAA SCITECH 2024; PDF, https://doi.org/10.2514/6.2024-1545

To extend electrospray thruster lifetime and improve performance, we must understand the relationship between particle emission conditions and the resulting evolved plume. To this end, we apply machine learning algorithms to simulated electrospray particle data to investigate correlations between particle properties at emission and further downstream. The strength of predictive ability and correlation rankings with emission properties are presented for final plume angle, among other final properties, and discussed in relation to the physical forces governing electrospray plume evolution. Illuminated correlations between particle properties inform diagnostic design by determining which properties offer the most insight towards predicting other properties.

Crandall, P., Cretel, C., Wirz, R., “RF Gridded Ion Thruster Design for Laboratory Experiments,” AIAA SCITECH 2024; PDF, https://doi.org/10.2514/6.2024-1549

RF gridded ion thrusters are simpler in construction than other gridded ion thrusters and have been shown to be more robust for air-breathing electric propulsion and alternative propellant applications than DC thrusters. ICP sources can be difficult to construct for new users who are unfamiliar with RF systems limiting adoption of RF thrusters. This work presents a basic overview of RF ion thruster concepts, ICP operating principles, antenna matching, and thruster design for new users. A lab model RF gridded ion thruster developed at the UCLA PESPL is described as a design example and preliminary performance values are presented.

Sabiston, G., Wirz, R., “Thrust Densification of Space Electric Propulsion Systems via Volumetrically Complex Materials,” AIAA SCITECH 2024; PDF, https://doi.org/10.2514/6.2024-1136

Thrust densification of space electric propulsion (EP) technologies is necessary to enable future ambitious space missions and exploration, such as crewed missions to Mars. EP densification is primarily limited by the ability of thruster materials to withstand extreme plasma conditions. This research investigates the interconnected dynamics of maximizing current enhancement, the subsequent challenges of sputtering and arcing erosion, and the implications of a promising new class of advanced materials, Volumetrically Complex Materials (VCMs), for space electric propulsion systems. In comparison to standard materials, VCMs show enhanced ability to manage high levels of plasma energy and electrical current due largely to the combined advantages of principles such as geometric trapping and plasma infusion. The mechanisms of energy management and sputterant transport within VCMs are examined to gain insight into optimal VCM geometries, and the potential for leveraging advanced additive manufacturing methods is explored. VCM arcing response and favorable sublimation erosion characteristics are also determined via coupled computational and experimental analyses. The findings underscore the potential of VCMs to revolutionize material design for challenging plasma-facing applications germane to EP, paving the way for more durable and efficient propulsion systems.

Konopliv, M., Wirz, R., Johnson, L., “Fast Optical Emission Spectroscopy Measurements of Time-Resolved Electron Temperature in a Hall Thruster,” AIAA SCITECH 2024; PDF, https://doi.org/10.2514/6.2024-2165

Time-dependent behavior of electrons can be critically important to Hall thruster discharge behavior. Fast Optical Emission Spectroscopy (FastOES) is a non-invasive diagnostic capable of measuring the time-resolved electron temperature of the plasma. The FastOES approach splits the collected light and isolates two distinct wavelengths that are detected by photomultiplier tubes, and amplified to a measurable signal. These measured emission lines are paired with a collisional-radiative model to determine time-resolved electron temperature. Using this technique, the FastOES results show that the electron temperature exhibits both temporal and spatial variations within the Hall thruster. There is a dynamic relationship between the electron temperature and the discharge current, with the electron temperature consistently exhibiting an out-of-phase relationship in correlation with the discharge current. Additionally, a loose scaling relationship was identified, providing valuable insights into the complex interplay within Hall thruster plasmas.

Cretel, C., Wirz, R., “Ion Optics Model for Rapid Assessment of Gridded Ion Thruster Mission Performance and Life,” AIAA SCITECH 2024; PDF, https://doi.org/10.2514/6.2024-1550

An increased need for high-power electric propulsion has placed greater importance on understanding the mechanisms that profoundly affect thruster life and performance during ground testing. To accurately predict life-ending mechanisms of gridded ion thrusters (GITs), time dependent erosion must be well understood across a range of thruster operating conditions, non-uniformities in grid geometry and discharge plasma parameters, over the entire exit plane of the thruster. This multivariate, spatially, and temporally evolving parameter space requires reduced order modeling to efficiently evaluate thruster design and operating conditions for space missions. This effort uses the CEX2D ion thruster grid model to evaluate grid performance, erosion, and electron backstreaming across discharge ion densities over the exit plane of the NSTAR thruster for operating conditions representative of conditions seen across the exit plane profile. The reduced order models exploit the direct correlation of CEX generation to grid erosion and then changes to the grid geometry with the evolution of the EBS limit. We identify that the physics mechanisms of charge exchange may be computationally expensive, thus, the results of this modeling effort will be to develop a physics informed, reduced order model for long-duration evaluation of grid performance and life.

Obenchain, R., Wirz, R., “Neutral Ingestion Compensation for Gridded Ion Thrusters via Modeling and Analysis,” AIAA SCITECH 2024; PDF, https://doi.org/10.2514/6.2024-1548

Electric propulsion facility effects can obfuscate performance and lifetime assessment for in-space operation. Neutral gas ingestion from the facility can be compensated by modifying discharge flow conditions. To assess this compensation for dc ion thrusters, this effort uses the DC-ION model to characterize the response of the discharge chamber and beam profile through compensation of the discharge cathode and plenum flows over a range of ingestion factors, λi, which is defined as the ratio of the mass flow of neutrals from the environment to the mass flow passing out through the thruster grids. Consistent with experimental observation, particular attention is given to changes to single and double ionization rates near the thruster axis where one often finds a peak in the beam profile. Overall, we find that local ingestion rates are very important and that a local neutral density ratio provides critical insight due to cathode plume ionization behavior. The results show that the most accurate compensation results from proportional changes to both the cathode and plenum flow rates.

Patrick Crandall, Richard Wirz, "Experimental Observations of Electrode Plasma-Surface Chemistry in Air-Breathing Gridded Ion Thrusters," APS Division of Plasma Physics Meeting Abstracts 2023. abstract

Graeme Sabiston, Richard Wirz, "Optimization of Additively Manufactured Plasma-facing Surfaces with Consideration of Plasma Infusion Effects," APS Division of Plasma Physics Meeting Abstracts 2023. abstract

Angelica Ottaviano, Yevgeny Raitses, Gary Wan, Evan Ostrowski, Shota Abe, Bruce Koel, Richard Wirz, Tim Bennett Team, "Direct measurements and spectroscopic analysis of secondary electron emission from carbon foams," APS Division of Plasma Physics Meeting Abstracts, 2023 abstract

Nicolas Rongione, Joshua Larson, Thomas Look, Phil Travis, Stephen Vincena, Frederick Skiff, Troy Carter, Richard Wirz, "Using Whistlers Waves from LAPD as a Plasma Diagnostic," APS Division of Plasma Physics Meeting Abstracts, 2023. abstract

Walker, M., Lev, D., et al., "Overview of the Joint AdvaNced PropUlsion InStitute," IEPC 2022, 37th International Electric Propulsion Conference, Cambridge, MA (June 2022)pdf

Chaplin, V., Johnson, L., Lobbia, R., Konopliv, M., Simka, T., Wirz, R., "Insights from Collisional-Radiative Models of Neutral and Singly-Ionized Xenon in Hall Thrusters," AIAA SCITECH, 2022. pdf

Sabiston, G. T., & Wirz, R. E., "Volumetrically Complex Materials for Reducing Electric Propulsion Facility Effects," IEPC 2022, 37th International Electric Propulsion Conference, Cambridge, MA (June 2022).pdf

Huh, H., Wirz, R., "Numerical Simulation of Cone-Jet and Emission Processes for Electrospray Thrusters," IEPC 2022, 37th International Electric Propulsion Conference, Cambridge, MA (June 2022). pdf

Wirz, R., Gorodetsky, A., Jorns, B., Walker, M., "Predictive Engineering Model for Life and Performance Assessment of High-Power Electric Propulsion Systems," IEPC 2022, 37th International Electric Propulsion Conference, Cambridge, MA (June 2022).pdf

Collins, A., Uchizono, N, Huh, H., Wirz, R., "Three-Dimensional Microscopy and Analysis of the Emission Cone Meniscus for Electrospray Thrusters," IEPC 2022, 37th International Electric Propulsion Conference, Cambridge, MA (June 2022). link

Wright, P. L., Uchizono, N. M., Collins, A. L., Wirz, R. E., "Characterization of a Porous Tungsten Electrospray Emitter," IEPC 2022, 37th International Electric Propulsion Conference, Cambridge, MA (June 2022).pdf

Ottaviano, A., & Wirz, R. (2022). Electron and Ion Induced Electron Emission from Volumetrically Complex Materials for Plasma Facing Surfaces. In APS Division of Plasma Physics Meeting Abstracts (Vol. 2022, pp. GP11-088).

Ottaviano, A., Wirz, R., Wan, G., Sabiston, G., Konopliv, M., & Thuppul, A., "Persistent Sputtering Yield Reduction in Plasma-Infused Materials for Plasma Propulsion and Fusion," APS Division of Plasma Physics Meeting Abstracts (Vol. 2022, pp. UO08-009).

Sabiston, G. T., & Wirz, R. E., "Thrust Densification of Space Electric Propulsion Systems via Volumetrically Complex Material," AIAA SCITECH, 2022. https://doi.org/10.2514/6.2024-1136

Crandall, P., & Wirz, R. E., "Air-Breathing Electric Propulsion CubeSat Mission Analysis," AIAA SCITECH, 2022. https://doi.org/10.2514/6.2022-2189, pdf

Uchizono, N., Wright, P., & Wirz, R. E., "Electrospray Thruster Facility Effects," AIAA SCITECH, 2022.pdf

Parmar, S. M., Collins, A. L., & Wirz, R. E., "Electrospray Plume modeling for Rapid Life and Performance Analysis," AIAA SCITECH, 2022. link, pdf

Breddan, M. J., Curry, D. R., Sharma, M., Richmond, M. O., Collins, A. L., Brieda, L., & Wirz, R. E., "Electrospray Plume Modeling: Study on Drag Influence," AIAA , 2022. https://doi.org/10.2514/6.2022-1358,pdf

Huh, H., & Wirz, R. E., "Electrohydrodynamic simulation of electrospray thruster extraction," AIAA SCITECH, 2022.https://doi.org/10.2514/6.2022-1359

Uchizono, N. M., & Wirz, R. E., "Facility effects for electrospray thrusters," AIAA SCITECH, 2022. https://doi.org/10.2514/6.2022-1361

Sophie F Peeters, Amber Armellini, Wi Jin Kim, Blake Haist, Zhitong Chen, Richard Obenchain, Weihong Ge, Aparna Bhaduri, Richard Wirz, Anthony C Wang, “Cold Atmospheric Plasma Exposure Decreases Chordoma Survival In Vitro,” Journal of Neurological Surgery Part B: Skull Base 85(S 01) (2024); https://doi.org/10.1055/s-0044-1779834

Wirz R.E., “Plasma Interactions with Complex Surfaces,” Bulletin of the American Physical Society, 74th Annual Gaseous Electronics Conference, 2021; https://meetings.aps.org/Meeting/GEC21/Session/SR53.7

Ottaviano A., Wirz R.E., “Secondary Electron Emission from Complex Surfaces,” Bulletin of the American Physical Society, Division of Plasma Physics, 2021; https://meetings.aps.org/Meeting/DPP21/Session/PP11.36

Konopliv M., Thuppul A., Wirz R.E., “Validation of Collisional Radiative Models for Low Temperature Xenon Plasmas,” Bulletin of the American Physical Society, Division of Plasma Physics, 2021; https://meetings.aps.org/Meeting/DPP21/Session/PP11.12

Thuppul A., Konopliv M., Wirz R.E., “Plasma Interactions and Sputtering Erosion for Plasma-Infused Volumetrically-Complex Surfaces,” Bulletin of the American Physical Society, Division of Plasma Physics, 2021; https://meetings.aps.org/Meeting/DPP21/Session/PP11.37

Wright P.L, Wirz R.E., “Transient Flow in Porous Electrospray Emitters,” AIAA Propulsion and Energy Forum, 2021; https://doi.org/10.2514/6.2021-3437

Chaplin V.H., Konopliv M., Simka T., Johnson L.K., Lobbia R.B., Wirz R.E., “Insights from Collisional-Radiative Models of Neutral and Singly-Ionized Xenon in Hall Thrusters,” AIAA Propulsion and Energy Forum, 2021; https://doi.org/10.2514/6.2021-3378

Konopliv M., Johnson L.K., Chaplin V.H., Lobbia R.B., Thuppul A., Simka T., Wirz R.E., “Collisional-Radiative Models of Neutral and Singly-Ionized Xenon in Hall Thrusters: Experimental Validation and Model Investigations,” AIAA Propulsion and Energy Forum, 2021; https://doi.org/10.2514/6.2021-3390

Wright P.L, Wirz R.E., “Fluid Mechanics of Porous Electrospray Thrusters,” SoCal Fluids, 2021

Pichitkul A., Sankar L.N., Wirz R.E., “Analysis of Biplane Blades for Large-Scale Offshore Wind Turbines,” SciTech 2021; https://doi.org/10.2514/6.2021-0814

Chen Z., Wirz R.E., “Microneedle patch-assisted combination of cold atmospheric plasma and immune checkpoint blockade,” 47th IEEE International Conference on Plasma Science (ICOPS-2020) and 2nd ASIA Pacific Conference on Plasma and Terahertz Science (APCOPTS-2020), December 6-10, 2020 (Presentation)

Chen Z., Garcia G., Arumugaswami V., Wirz R.E., “Cold atmospheric plasma for SARS-CoV-2 inactivation,” medRxiv (2020); https://www.medrxiv.org/content/10.1101/2020.09.17.20192872v1

Chen, Z.; Wirz, R.E., Cold Atmospheric Plasma for COVID-19. Preprints 2020, 2020040126; https://www.preprints.org/manuscript/202004.0126/v1

Ziemer J.K., Marrese-Reading C.M., Arestie S.M., Demmons N.R., Wirz R.E., Collins A.L., Gamero-Castaño M., “Progress on Developing LISA Microthruster Technology,” AIAA Propulsion and Energy Forum, AIAA 2020-3609, 2020; https://doi.org/10.2514/6.2020-3609

Wirz R.E., “Improving Electrospray Thruster Impulse and Life,” Joint Army Navy NASA Air Force (JANNAF) Interagency Propulsion Committee Meeting, Tampa FL. (Dec 2019)

Wirz R.E., Samples S.A., “The Miniature Xenon Ion (MiXI) Thruster: Development and Capabilities,” Joint Army Navy NASA Air Force (JANNAF) Interagency Propulsion Committee Meeting, Tampa FL. (Dec 2019)

Wirz R.E., Collins A.L., Chen Z., Huerta C., Li G.Z., Samples S.A., Thuppul A., Wright P.L., Uchizono N.M., Huh H., Davis M.J., Ottaviano A., “Electric Propulsion Activities at the UCLA Plasma & Space Propulsion Laboratory,” IEPC-2019-547, 36th International Electric Propulsion Conference, Vienna, Austria, (Sept. 2019)

Ziemer J.K., Marrese-Reading C.M., Arestie S.M., Conroy D.G., Leifer S.D., Demmons N.R., Gamero-Castaño M., Wirz R.E., “LISA Colloid Microthruster Technology Development Plan and Progress,” IEPC-2019-547, 36th International Electric Propulsion Conference, Vienna, Austria, (Sept. 2019)

Uchizono N.M., Collins A.L., Thuppul A., Wright P.L., Eckhardt D.Q., Ziemer J.K., Wirz R.E., “Electrospray Transient Emission Behavior and Spatial Stability,” IEPC-2019-368, 36th International Electric Propulsion Conference, Vienna, Austria, Sept. 2019

Huh H., Wirz R.E., “Numerical Simulation of Electrospray Extraction for Highly Conductive Propellants,” IEPC-2019-565, 36th International Electric Propulsion Conference, Vienna, Austria, Sept. 2019

Thuppul A., Collins A.L., Wright P.L., Uchizono N.M., Wirz R.E., “Spatially-Resolved Mass Flux and Current Measurements for Electrospray Plumes,” IEPC-2019-571, 36th International Electric Propulsion Conference, Vienna, Austria, Sept. 2019

Collins A.L., Thuppul A., Wright P.L., Uchizono N.M., Huh H., Davis M.J., Ziemer J.K., Demmons N.R., Wirz R.E., “Assessment of grid impingement for electrospray thruster lifetime,” IEPC-2019-213, 36th International Electric Propulsion Conference, Vienna, Austria, Sept. 2019

Davis M.J., Collins A.L., Wirz R.E., “Electrospray Plume Evolution Via Discrete Simulations,” IEPC-2019-590, 36th International Electric Propulsion Conference, Vienna, Austria, Sept. 2019

Wright P.L., Huh H., Uchizono N.M., Thuppul A., Wirz R.E., “A Novel Variable-Mode Emitter for Electrospray Thrusters,” IEPC-2019-650, 36th International Electric Propulsion Conference, Vienna, Austria, Sept. 2019

Samples S.A., Wirz R.E., “Development Status of the Miniature Xenon Ion Thruster,” IEPC-2019-143, 36th International Electric Propulsion Conference, Vienna, Austria, (Sept. 2019)

Ottaviano A., Li G.Z., Huerta C., Thuppul A., Chen Z., Dodson C.A., Wirz R.E., “Plasma Material Interactions for Electric Propulsion: Challenges, Approaches, and Future,” IEPC-2019-157, 36th International Electric Propulsion Conference, Vienna, Austria, (Sept. 2019)

Wirz R. E., Collins A. C., Thuppul A., Wright P. L., Uchizono N. M., Huh H., Davis M. J., “Electrospray Thruster Performance and Lifetime Investigation for the LISA Mission,” AIAA-2019-3816, AIAA Propulsion and Energy Forum, Indianapolis, IN, USA, (Aug. 2019)

Wright P.L., Huh H., Uchizono N.M., Thuppul A., Wirz R.E., “A Novel Variable-Mode Emitter for Electrospray Thrusters,” IEPC-2019-650, 36th International Electric Propulsion Conference, Vienna, Austria, Sept. 2019

Samples S.A., Wirz R.E., “Development Status of the Miniature Xenon Ion Thruster,” IEPC-2019-143, 36th International Electric Propulsion Conference, Vienna, Austria, (Sept. 2019)

Ottaviano A., Li G.Z., Huerta C., Thuppul A., Chen Z., Dodson C.A., Wirz R.E., “Plasma Material Interactions for Electric Propulsion: Challenges, Approaches, and Future,” IEPC-2019-157, 36th International Electric Propulsion Conference, Vienna, Austria, (Sept. 2019)

Wirz R. E., Collins A. C., Thuppul A., Wright P. L., Uchizono N. M., Huh H., Davis M. J., “Electrospray Thruster Performance and Lifetime Investigation for the LISA Mission,” AIAA-2019-3816, AIAA Propulsion and Energy Forum, Indianapolis, IN, USA, (Aug. 2019) https://doi.org/10.2514/6.2019-3816

Ziemer J.K., Marrese-Reading C.M., Arestie S.M., Conroy D.G., Leifer S.D., Ortega A.L., Demmons N.R., Gamero-Castaño M., Wirz R.E., “Incorporating Lessons Learned into LISA Colloid Microthruster Technology Development,” AIAA-2019-3816, AIAA Propulsion and Energy Forum, Indianapolis, IN, USA, (Aug. 2019) https://arc.aiaa.org/doi/10.2514/6.2019-3814

Shumlak, B. Açikmeşe, E. L. Claveau, E. G. Forbes, R. P. Golingo, B. A. Nelson, Y. Raitses, R. E. Wirz, Y. Zhang, “Fusion space propulsion system based on the sheared flow stabilization Z-pinch”, 60th Annual Meeting of APS-DPP (Presentation) (2018)

Wright P.L., Thuppul A., Wirz R.E., “Life-Limiting Emission Modes for Electrospray Thrusters,” AIAA-2018-4726, 54th AIAA/SAE/ASEE Joint Propulsion Conference, Cincinnati, OH (July 2018) https://arc.aiaa.org/doi/abs/10.2514/6.2018-4726

Thuppul A., Wright P.L., Wirz R.E., “Lifetime Considerations and Estimation for Electrospray Thrusters,” AIAA-2018-4652, 54th AIAA/SAE/ASEE Joint Propulsion Conference, Cincinnati, OH (July 2018) https://arc.aiaa.org/doi/abs/10.2514/6.2018-4652

Huerta C.E., Wirz R.E., “DC-ION model validation and convergence studies,” AIAA-2018-4813, 54th AIAA/SAE/ASEE Joint Propulsion Conference, Cincinnati, OH (July 2018) https://arc.aiaa.org/doi/abs/10.2514/6.2018-4813

Li G., Huerta C.E., Wirz R.E., “Computational Modeling of an Axial Ring Cusp Hybrid Discharge for the MiXI thruster,” AIAA-2018-4814, 54th AIAA/SAE/ASEE Joint Propulsion Conference, Cincinnati, OH (July 2018) https://arc.aiaa.org/doi/abs/10.2514/6.2018-4814

Samples S.A., Li G., Wirz R.E., “Performance Testing and Development of the MiXI Thruster with the ARCH Discharge,” AIAA-2018-4648, 54th AIAA/SAE/ASEE Joint Propulsion Conference, Cincinnati, OH (July 2018) https://arc.aiaa.org/doi/abs/10.2514/6.2018-4648

Russell, C.T., Wirz, R.E., Lai, H.R., Li, J.Y., Connors, M., “Smallsats with Ion Propulsion: An Affordable Approach to Meeting the Needs of Planetary Defense and Planetary Science at 1AU,” No. 1964, id.1270, 48th Lunar and Planetary Science Conference, The Woodlands, Texas (March 2017) 2017LPI….48.1270R

Shinn M., Nithyanandam K., Barde A., Wirz R.E., “Thermal Analysis of Elemental Sulfur in a Shell-and-Tube Configuration for Thermal Energy Storage Applications,” IMECE2016-67389, ASME 2016 International Mechanical Engineering Congress and Exposition, Phoenix, Arizona (Nov. 2016), http://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/90990/v06bt08a063-imece2016-67389.pdf

Patino M., Yevgeny R., Wirz R.E., “Electron Emission from Nano and Microstructured Materials for Fusion and Plasma Discharge Applications,” APS Division of Plasma Physics Meeting, Poster, (Oct 2016) http://adsabs.harvard.edu/abs/2016APS..DPPUO4013P

Dankongkakul B., Wirz R.E., “Design of Miniature Ring-Cusp Ion Thrusters via Analysis of Discharge EEDF and Plasma Parameter Mapping,” AIAA-2016-4545, 52nd AIAA/SAE/ASEE Joint Propulsion Conference, Salt Lake City, UT (July 2016) https://doi.org/10.2514/6.2016-4545

Huerta C.E., Wirz R.E., “Surface Geometry Effects on Secondary Electron Emission Via Monte Carlo Modeling,” AIAA-2016-4840, 52nd AIAA/SAE/ASEE Joint Propulsion Conference, Salt Lake City, UT (July 2016) https://doi.org/10.2514/6.2016-4840

Dodson C.A., Perez-Grande D., Jorns B., Goebel D.M., Wirz R.E., “Laser-induced Fluorescence Measurements of Energetic Ions in a 100-A LaB6 Hollow Cathode Plume,” AIAA-2016-4838, 52nd AIAA/SAE/ASEE Joint Propulsion Conference, Salt Lake City, UT (July 2016) https://doi.org/10.2514/6.2016-4838

Li G.Z., Dodson C.A., Wirz R.E, Matlock T.S., Goebel D.M, “Implementation of in situ diagnostics for sputter yield measurements in a focused plasma,” AIAA-2016-4841, 52nd AIAA/SAE/ASEE Joint Propulsion Conference, Salt Lake City, UT (July 2016) https://doi.org/10.2514/6.2016-4841

Marrese-Reading C.M, Anderson J., Jung-Kubiak C., Greer F., Rouhi N., Wilson D., White V., Dickie M., Mueller R., Singh V., Mackie W., Wirz R.E., Gamero-Castano M., “Silicon Emitter Needle and Array Design for Indium Electrospray Arrays for Spacecraft Propulsion,” AIAA-2016-4547, 52nd AIAA/SAE/ASEE Joint Propulsion Conference, Salt Lake City, UT (July 2016) https://doi.org/10.2514/6.2016-4547

Marrese-Reading C.M., Anderson J., Jung-Kubiak C., Polk J., Singh V., Yee K., White V., Wilson D., Bruneau P., Rouhi N., Greer F., Borgonia J.P., Dickie M., Muller R., Ziemer J., Gray A., Mueller J., Wirz R.E

Zhao J., Luo W., Guo J., Matlock T., Wirz R., Randall C. A., Lanagan M. T., “Microwave Generated Plasmas in Ring Resonators,” Microwave Materials and Applications, MMA2016.org, Seoul Korea, Presentation (July 5, 2016)

Wells, P., Nithyanandam, K., Wirz, R.E., “Cost Optimal Strategies of High Temperature Thermal Energy Storage Systems in Combined Heat and Power Applications,” ASME 2016 10th International Conference on Energy Sustainability, ASME ES2016-59471 Charlotte, NC (June 2016) http://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/90140/v001t03a006-es2016-59471.pdf

Nithyanandam, K., Barde, A., Lakeh, R.B., Tse, L., Wirz, R.E., “Heat Transfer Behavior of Sulfur for Thermal Storage Applications,” ASME 2016 10th International Conference on Energy Sustainability, Charlotte, NC (June 2016) http://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/90142/v001t05a008-es2016-59470.pdf

Nithyanandam, K., Barde, A., Lakeh, R.B., Wirz, R.E., “Design and Analysis of Low-Cost Thermal Storage System for High Efficiency Concentrating Solar Power Plants,” ASME 2016 10th International Conference on Energy Sustainability, Charlotte, NC (June 2016) http://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/90142/v001t05a007-es2016-59469.pdf

Barde, A., Shinn, M., Nithyanandam, K., Lakeh, R.B., Wirz, R.E., “Sulfur-Based Thermal Storage System: Thermal Characteristics and Performance Analysis,” ASME 2016 10th International Conference on Energy Sustainability, Charlotte, NC, Presentation (June 2016)

Lakeh R.B., Nithyanandam K., Barde, A., Tse L., Wirz, R.E., “Effect of Viscosity Variations on Charge and Discharge Time of a Sulfur-Based Thermal Energy Storage System,” ASME 2016 10th International Conference on Energy Sustainability, Charlotte, NC (June 2016) http://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/90142/v001t05a002-es2016-59161.pdf

Chiu P.K., Wirz R.E., “Optimal Aerodynamic Design of a Biplane Wind Turbine Blade,” AIAA 2016-1266, 34th Wind Energy Symposium, San Diego, CA (Jan. 2016) https://doi.org/10.2514/6.2016-1266

Lakeh, R.B., Guerrero, Y.B., Nithyanandam, K., Wirz, R.E., “Assessment of Natural Convection Heat Transfer in an Isochoric Thermal Energy Storage System,” ASME IMECE205-52284, ASME International Mechanical Engineering Congress & Exposition (IMECE), Houston, TX (Nov. 2015) https://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/86890/v06at07a058-imece2015-52284.pdf

Huerta C.E., Matlock T.S., Wirz R.E., “Validation of a Plasma-Facing Surface Sputtering and Deposition View Factor Model,” AIAA SPACE 2015, Pasadena, CA (Sept. 2015) https://doi.org/10.2514/6.2015-4503

Wirz R.E., “Miniature Ion Thrusters: A Review of Modern Technologies and Mission Capabilities,” IEPC-2015-275, 34th International Electric Propulsion Conference and 6th Nano-satellite Symposium, Kobe, Japan (July 2015) http://erps.spacegrant.org/uploads/images/2015Presentations/IEPC-2015-275_ISTS-2015-b-275.pdf

Araki S.J., Wirz R.E., “Modeling of Elastic Collisions between High Energy and Slow Neutral Atoms,” IEPC-2015-202, 34th International Electric Propulsion Conference and 6th Nano-satellite Symposium, Kobe, Japan (July 2015) http://www.dtic.mil/dtic/tr/fulltext/u2/a626028.pdf

Matlock T.S., Dodson C.A., Goebel D.M., Wirz R.E., “Measurements of Transport due to Low Frequency Oscillations in a Rotating Hollow Cathode Plasma,” IEPC-2015-137, 34th International Electric Propulsion Conference and 6th Nano-satellite Symposium, Kobe, Japan (July 2015) http://erps.spacegrant.org/uploads/images/2015Presentations/IEPC-2015-137_ISTS-2015-b-137.pdf

Conversano R.W., Goebel D.M., Hofer R.R., Matlock T.S., Wirz R.E., “Magnetically Shielded Miniature Hall Thruster: Design Improvement and Performance Analysis,” IEPC-2015-100, 34th International Electric Propulsion Conference and 6th Nano-satellite Symposium, Kobe, Japan (July 2015) http://www.wirz.seas.ucla.edu/sites/default/files/publications/conversano2015magnetically-shielded-miniature-hall-thruster-design-improvement-and-performance.pdf

Lakeh, R.B., Kavehpour, H.P., Wirz, R. E., Lavine, A.S., “Transient Turbulent Natural Convection In Vertical Tubes For Indirect Thermal Energy Storage,” ASME ES2015-49092, ASME 9th International Conference on Energy Sustainability, San Diego, CA (July 2015) http://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/86275/v002t18a003-es2015-49092.pdf

Tse, L, Wirz, R.E., Lavine, A.S., “Optimal Operation Strategies for Thermal Energy Storage Systems in Solar Thermal Power Plants,” ASME 9th International Conference on Energy Sustainability, San Diego, CA (July 2015) (Best Student Paper) http://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/86275/v002t18a001-es2015-49053.pdf

Conversano R.W., Goebel D.M., Hofer R.R., Mikellides I.G., Katz I., Wirz R.E.., “Development and Validation Overview for the Design of Low Power Magnetically Shielded Hall Thrusters,” 62nd JANNAF Propulsion Meeting, Nashville, TN (June 2015), Dist C.

Lakeh R.B., Kavehpour H.R., Wirz R.E., Lavine A.S., “Transient turbulent natural convection in vertical tubes for thermal energy storage,” IMECE2014-37773, ASME 2014 International Mechanical Engineering Conference and Exposition, Montreal, Quebec, Canada (Nov. 2014) http://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/83085/v06bt07a049-imece2014-37773.pdf

Conversano R.W., Arora N., Goebel D.M., Wirz R.E., “Preliminary Mission Capabilities Assessment of a Magnetically Shielded Miniature Hall Thruster,” IAC-14.C4.4.4, 65th International Aerospace Congress, Toronto, Canada (Oct. 2014) http://www.wirz.seas.ucla.edu/sites/default/files/publications/conversano2014preliminary-mission-capabilities-assessment-of-a-magnetically-shielded-miniature-hall_0.pdf

Matlock T., Goebel D., Wirz R.E., “An Investigation of Low Frequency Plasma Instabilities in a Cylindrical Hollow Cathode Discharge,” AIAA 6.2014-3508, 50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Cleveland, OH (July 2014) https://doi.org/10.2514/6.2014-3508

Araki S.J., Wirz R.E., “Magnetic Field Aligned Mesh for Ring-Cusp Discharge Chambers,” 50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Cleveland, OH (July 2014) https://doi.org/10.2514/6.2014-3830

Tse, L.A., Baghaei Lakeh, R., Wirz. R.E., Lavine, A.S., “Exergy-Based Optimization of Sub- and Supercritical Thermal Energy Storage Systems,” ASME ES204-6302, ASME 8th International Conference on Energy Sustainability, Boston, MA (July 2014) https://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/81450/v002t12a001-es2014-6302.pdf

Conversano R.W., Goebel D.M., Mikellides I.G., Hofer R.R., Matlock T.S., Wirz R.E., “Magnetically Shielded Miniature Hall Thruster: Performance Assessment and Status Update,”50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Cleveland, OH (July 2014) https://doi.org/10.2514/6.2014-3896

Lakeh, R.B., Lavine, A.S., Kavehpour, H.P., Wirz, R.E, “Investigation of Transient, Turbulent Natural Convection in Vertical Tubes for Thermal Energy Storage in Supercritical CO2,” 66th Annual Meeting of the Fluid Mechanics Division of the American Physical Society, Pittsburgh, PA (Nov. 2013) 2013APS..DFD.M2003B

Lakeh R.B., Kavehpour H.P., Lavine, A.S., Ganapathi G.B., Wirz, R.E., “Study of turbulent natural convection in vertical storage tubes for supercritical thermal storage system,” ASME IMECE2013-62716, ASME International Mechanical Engineering Congress & Exposition (IMECE), San Diego, CA (Nov. 2013) http://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/79154/v06bt07a030-imece2013-62716.pdf

Bran-Anleu, G., Lavine, A.S., Wirz, R.E., Lakeh R.B., Kavehpour, H.P., “An Algorithm to Determine the Optimized Data Range in Transient Hotwire Thermal Property Measurement,” ASME IMECE2013-64940, ASME International Mechanical Engineering Congress & Exposition (IMECE), San Diego, CA (Nov. 2013) http://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/79154/v06bt07a030-imece2013-62716.pdf

Furst, B., Lavine, A.S., Lakeh, R.B., Wirz, R.E., “Isobaric, Isochoric and Supercritical Thermal Energy Storage in R134a,” ASME IMECE2013-64947, ASME International Mechanical Engineering Congress & Exposition (IMECE), San Diego, CA (Nov. 2013) http://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/79154/v06bt07a072-imece2013-64947.pdf

Dodson C.A., Wirz R.E., Matlock T.S., “Computational Modeling of a High Power Plasma Source for Material Interaction Experiments,” IEPC-2013-224, 33rd International Electric Propulsion Conference, Washington, D.C. (Oct. 2013) http://www.wirz.seas.ucla.edu/sites/default/files/publications/dodson2013computational-modeling-of-a-high-power-plasma-source-for-material-interaction-experiments.pdf

Araki S.J., Wirz R.E., “Particle Simulation of Near-Surface Cusp Confinement of Weakly Ionized Plasma,” IEPC-2013-349, 33rd International Electric Propulsion Conference, Washington, D.C. (Oct. 2013) http://wirzresearchgroup.com/sites/default/files/publications/araki2013particle-simulation-of-near-surface-cusp-confinement-of-weakly-ionized-plasma.pdf

Matlock T.S., Goebel D.M., Conversano R., Wirz R.E., “Near anode plasma in the plasma interaction facility at UCLA,” IEPC-2013-327, 33rd International Electric Propulsion Conference, Washington, D.C. (Oct. 2013) http://erps.spacegrant.org/uploads/images/images/iepc_articledownload_1988-2007/2013index/l3ku1eg5.pdf

Dankongkakul B., Wirz R.E., “Electron Loss at a Magnetic Cusp for a Range of Upstream Magnetic Field Conditions,” IEPC-2013-331, 33rd International Electric Propulsion Conference, Washington, D.C. (Oct. 2013) http://www.iepc2013.org/get?id=331

Patino M.I., Raitses Y., Koel B.E., Wirz R.E., “Application of Auger Spectroscopy for Measurement of Secondary Electron Emission from Conducting Material for Electric Propulsion Devices,” IEPC-2013-320, 33rd International Electric Propulsion Conference, Washington, D.C. (Oct. 2013) http://www.wirz.seas.ucla.edu/~wirzrese/sites/default/files/publications/patino2013application-of-auger-spectroscopy-for-measurement-of-secondary-electron-emission-from.pdf

Conversano R., Goebel D.M., Hofer R.R., Matlock T.S., Wirz R.E., “Magnetically Shielded Miniature Hall Thruster: Development and Initial Testing,” IEPC-2013-201, 33rd International Electric Propulsion Conference, Washington, D.C. (Oct. 2013) http://erps.spacegrant.org/uploads/images/images/iepc_articledownload_1988-2007/2013index/h8gqm62v.pdf

Dankongkakul B., Araki S. J., Wirz R.E., “Influence of Upstream Field Structure on Primary Electron Loss for a Permanent Magnet Cusp,” AIAA-2013-3963, 49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, San Jose, CA (July 2013) https://doi.org/10.2514/6.2013-3963

Matlock T.S., Goebel D.M., Conversano R.W., Wirz R.E., “The Plasma Interactions Facility at UCLA,” AIAA-2013-4132, 49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, San Jose, CA (July 2013) https://doi.org/10.2514/6.2013-4132

Lakeh R.B., Lavine, A., Kavehpour H.P., Ganapathi G.B., Wirz, R.E, “Effect of natural convection on thermal energy storage in supercritical fluids,” ASME ES2013-18079, ASME 7th International Conference on Energy Sustainability, Minneapolis, MN (July 2013) http://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/77295/v001t05a001-es2013-18079.pdf

Tse L., Stopin A., Ganapathi, G. B., Garcia-Garibay M.A., Wirz, R.E., “Thermal testing of organic fluids for supercritical thermal energy storage systems,” ASME ES2013-18195, ASME 7th International Conference on Energy Sustainability, Minneapolis, MN (July 2013) http://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/77293/v001t03a007-es2013-18195.pdf

Ganapathi G. B, Berisford D., Furst B., Bame D., Pauken M., Wirz R.E., “A 5 kWht lab-scale demonstration of a novel thermal energy storage concept with supercritical fluids,” ASME ES2013-18182, ASME 7th International Conference on Energy Sustainability, Minneapolis, MN (July 2013)http://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/77305/v001t15a005-es2013-18182.pdf

Wirz R.E., “Near-Surface Cusp Confinement of Micro-Scale Plasma,” 2012 AFOSR Space Propulsion and Power Program Review, Arlington, VA (Sept. 2012) http://www.dtic.mil/get-tr-doc/pdf?AD=ADA568238

Wirz R.E., Araki S. J., Dankongkakul B., “Near-Surface Cusp Confinement for Weakly Ionized Plasma,” AIAA-2012-3948, 48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Atlanta, GA (Aug. 2012) https://doi.org/10.2514/6.2012-3948

Patino M., Chu L., Wirz R.E., “Ion-Neutral Collision Analysis for a Well-Characterized Plasma Experiment,” AIAA-2012-4119, 48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Atlanta, GA (Aug. 2012) https://doi.org/10.2514/6.2012-4119

Mao H.-S., Goebel D., Wirz R.E., “Plasma Structure of Miniature Ring-Cusp Ion Thruster Discharges,” AIAA-2012-4021, 48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Atlanta, GA (Aug. 2012) https://doi.org/10.2514/6.2012-4021

Ganapathi G.B., Wirz R.E., “High density Thermal Energy Storage with Supercritical Fluids,” ASME ESl2012-91008, ASME 6th International Conference on Energy Sustainability, San Diego, CA (July 2012) http://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/75584/699_1.pdf

Stopin A., Ganapathi G. B., Wirz R.E., Garcia-Garibay M., “Stability of organic fluids at high temperature for thermal energy storage,” ASME 6th International Conference on Energy Sustainability, San Diego, California (July 2012) (Poster)

Tse, L., Ganapathi, G.B., Wirz R.E., Lavine, A., “System Modeling for a Supercritical Thermal Energy Storage System,” ASME ES2012-91011 ASME 6th International Conference on Energy Sustainability, San Diego, California (July 2012) http://proceedings.asmedigitalcollection.asme.org/data/conferences/asmep/75584/691_1.pdf

Choi, D., Wirz R.E., Ganapathi, G. B., Kavehpour, H. P., “Numerical Simulation of Heat Transfer to a Supercritical Thermal Fluid,” ASME 6th International Conference on Energy Sustainability, San Diego, California (July 2012) (Presentation)

Stopin A., Ganapathi G., Wirz R.E., Garcia-Garibay M., “Stability of organic fluids at high temperature for thermal energy storage,” 16th Green Chemistry & Engineering Conference, Washington D.C. (June 2012) (Presentation)

Johnson P., Wirz R.E., “Structural design of spars for 100-meter biplane wind turbine blades,” AWEA Windpower Conference, Atlanta, GA (June 2012) (Presentation)

Chiu P., Johnson P., Wirz R.E., “Aerodynamic Performance of Biplane Airfoils for Wind Turbine Blades,” AWEA Windpower Conference, Atlanta, GA (June 2012) (Presentation)

Mao H.-S., Wirz R.E., “Plasma Map of Miniature Ring-Cusp Ion Thrusters,” UCLA Mechanical and Aerospace Engineering Research and Technology Review, Los Angeles, CA (April 2012) (Poster)

Araki S. J., Wirz R.E., “Collision Modeling of High Velocity Ions in a Quiescent Gas,” UCLA Mechanical and Aerospace Engineering Research and Technology Review, Los Angeles, CA (April 2012) (Poster)

Patino M., Chu L., Wirz R.E., “Simplified Plasma Experiment for Investigation of Plasma Diffusion and Transport Mechanisms,” UCLA Mechanical and Aerospace Engineering Research and Technology Review, Los Angeles, CA (April 2012) (Poster)

Tse, L., Ganapathi, G. B., Wirz R.E., Lavine, A., “Thermal Energy Storage with Supercritical Fluids,” UCLA Mechanical and Aerospace Engineering Research and Technology Review, Los Angeles, CA (April 2012) (Poster)

Wirz R.E., Ganapathi G. B., “Thermal Energy Storage with Supercritical Fluids,” ARPA-E Energy Innovation Summit, Washington D.C. (Feb. 2012) (Poster)

Wirz R.E., Stopin A., “Thermal Energy Storage with Supercritical Fluids, Fluid Screening and Chemical Analysis,” ARPA-E Energy Innovation Summit, Washington D.C. (Feb. 2012) (Poster)

Wirz R.E., Tse L., “Thermal Energy Storage with Supercritical Fluids, System Modeling for Supercritical Thermal Energy Storage and Heat Transfer Behavior of Supercritical Fluids,” ARPA-E Energy Innovation Summit, Washington D.C. (Feb. 2012) (Poster)

Ganapathi G.B., Wirz R.E., “Thermal Energy Storage with Supercritical Fluids (Super TES),” Clean Tech India-USA Business Conference (Oct. 2011) https://trs.jpl.nasa.gov/bitstream/handle/2014/43596/11-4863_A1b.pdf?sequence=1

Wirz R.E., Chu L., Patino M., Mao H., Araki S.J., “Well-Characterized Plasma Experiments for Validation of Computational Models”, IEPC-2011-122, 32nd International Electric Propulsion Conference, Kurhaus, Wiesbaden, Germany (Sept. 2011) https://www.researchgate.net/publication/267959565

Conversano R., Wirz R.E., “CubeSat Lunar Mission Using a Miniature Ion Thruster,” AIAA-2011-6083, 47th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, San Diego, CA (July 2011) https://doi.org/10.2514/6.2011-6083

Wirz R.E., Johnson P., “Aero-Structural Performance of Multiplane Wind Turbine Blades,” AIAA-2011-3025, 29th AIAA/ASME/SAE/ASEE Applied Aerodynamics Conference, Honolulu, Hawaii (June 2011) https://doi.org/10.2514/6.2011-3025

Mao H.-S., Wirz R.E., “Comparison of Charged Particle Tracking Methods for Non-Uniform Magnetic Fields”, AIAA-2011-3739, 42nd AIAA Plasmadynamics and Lasers Conference, Honolulu, Hawaii (June 2011) https://doi.org/10.2514/6.2011-3739

Araki S.J., Wirz R.E., “Collision Modeling for High Velocity Ions in a Quiescent Gas” AIAA-2011-3740, 42nd AIAA Plasmadynamics and Lasers Conference, Honolulu, Hawaii (June 2011) https://doi.org/10.2514/6.2011-3740

Aspe S., Wirz R.E., “Computational Model for Vertical Axis Wind Turbine (VAWT) Design,” Wind Power 2011, Anaheim, CA (May 2011) (Poster Session)

Tarzi Z., Speyer J., Wirz R.E., “Optimum Low-Thrust Elliptical Transfer for Power Limited Spacecraft using Numerical Averaging and Continuously Variable Thrust,” Proceedings of the 21st AAS Space Flight Mechanics Meeting, pp. 11-234, New Orleans, LA (Feb. 2011)

Wirz R.E., “Coupled Analysis of Ion Thruster Grid Erosion and Electron Backstreaming,” Space Propulsion 2010, San Sebastian, Spain (May 2010)

Marrese-Reading, C.M., Ziemer, J.K., Scharf, D.P., Martin-Mur, T.J., Thompson, P., Mueller, J., Wirz R.E., “Mission enabling and enhancing spacecraft capabilities with microNewton electric propulsion,” IEEE Aerospace Conference, Big Sky, MT (March 2010) 10.1109/AERO.2010.5447032

Martin S.R., Scharf D.P., Wirz R.E., Purceli G., Rodriguez J., “A Mid-Infrared Space Observatory for Characterizing Exoplanets,” ASP Conference Series Vol.430, Barcelona, Spain (Sept. 2009) http://adsabs.harvard.edu/full/2010ASPC..430..493M

Wirz R.E., “Long Duration Assessment of Electron Backstreaming for Ion Optics,” IEPC-2009-164, 31st International Electric Propulsion Conference, Ann Arbor, MI (Sept. 2009) http://erps.spacegrant.org/uploads/images/images/iepc_articledownload_1988-2007/2009index/IEPC-2009-164.pdf

Marrese-Reading, C.M., Ziemer, J.K., Scharf, D.P., Martin-Mur, T.J., Thompson, P., Mueller, J., Wirz R.E., “MicroNewton Electric Propulsion Requirements to Enhance or Enable Future NASA Missions,” IEPC-2009-216, 31st International Electric Propulsion Conference, Ann Arbor, Michigan (Sept. 2009)

Tarzi Z., Speyer J., Wirz R.E., “Optimum Low-Thrust Transfer between Arbitrary Elliptic Orbits for Power-Limited Spacecraft using Asymptotic Expansions and Averaging,” IEPC-2009-222, 31st International Electric Propulsion Conference, Ann Arbor, Michigan (Sept. 2009) http://erps.spacegrant.org/uploads/images/images/iepc_articledownload_1988-2007/2009index/IEPC-2009-222.pdf

Marrese-Reading, C., St. Vaughn, J., Prakash, R., Singh, G., Frisbee, R., Mandic, M., Pain, R., Slade, W., Rooney, D., Leipold, D., Ramos, A., Pierce, D., Corliss, J., Tutterow, R., True, W., Robbins, R., Barr, D., Stephens, J., Wirz R.E., “Orion spacecraft nominal and contingency earth landing retro rocket system options,” IEEE Aerospace Conference, Big Sky, MT (March 2009) 10.1109/AERO.2009.4839349

Wirz R.E., Katz I., Goebel D., Anderson J., “Electron Backstreaming Determination for Ion Thrusters,” AIAA-2008-4732, 44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Hartford, CT (July 2008) https://doi.org/10.2514/6.2008-4732

Wirz R.E., Anderson J., Katz I., Goebel D., “Time-Dependent Erosion of Ion Optics,” AIAA-2008-4529, 44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Hartford, CT (July 2008) https://doi.org/10.2514/6.2008-4529

Lengyel A., Wirz R.E., “Miniature Valve for Xenon Thrusters,” AIAA-2008-5085, 44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Hartford, CT (July 2008) https://doi.org/10.2514/6.2008-5085

Goebel D.M., Polk J., Wirz R.E., Snyder J.S., Mikellides I.G., Katz I., Anderson J. “Qualification of Commercial XIPS Ion Thrusters for NASA Deep Space Missions,” AIAA-2008-4914, 44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Hartford, CT (July 2008) https://doi.org/10.2514/6.2008-4914

Mueller J., Ziemer J., Hofer R., Wirz R.E., O’Donnell T., “A Survey of Micro-Thrust Propulsion Options for Microspacecraft and Formation Flying Missions,” 5th Annual CubeSat Developers Workshop, San Luis Obispo, CA (April 2008) https://www.researchgate.net/publication/268414397

Martin, S., Scharf, D.P., Wirz R.E., Lay O., McKinstry D., Mennesson B., Purcell G., Rodriguez J., Scherr L., Smith J.R., Wayne L., “Design Study for a Planet-Finding Space Interferometer,” IEEE Aerospace Conference, Big Sky, MT (March 2008) 10.1109/AERO.2008.4526410

Wirz R.E., Anderson J. R., Goebel D., Katz I., “XIPS Ion Thruster Grid Erosion Assessment for Deep Space Missions,” IEPC-2007-265, 30th International Electric Propulsion Conference, Florence, Italy (Sept. 2007) http://erps.spacegrant.org/uploads/images/images/iepc_articledownload_1988-2007/2007index/IEPC-2007-265.pdf

Martin S., Scharf D., Wirz R.E., Lay O., McKinstry D., Mennesson B., Purcell G., Rodriguez J., Scherr L., Smith J. R., Wayne L., “TPF-Emma: concept study of a planet finding space interferometer,” Proc. SPIE Vol. 6693, Techniques and Instrumentation for Detection of Exoplanets III, San Diego, CA (Sept. 2007) https://doi.org/10.1117/12.734835

Wirz R.E., Shariff S., “Ground Effects for CEV Vertical Retrorockets,” AIAA-2007-5758, 43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Cincinnati, OH (July 2007) https://doi.org/10.2514/6.2007-5758

Wirz R.E., Goebel D., “Ion Thruster Discharge Performance per Magnetic Field Topography,” AIAA 2006-4487, 42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Sacramento, CA (July 2006) (Best Paper of “Ion Thruster Physics and Modeling” Session) https://doi.org/10.2514/6.2006-4487

Wirz R.E., Sullivan R., Przybylowski J., Silva M., “Discharge Hollow Cathode and Extraction Grid Analysis for the MiXI Ion Thruster,” AIAA 2006-4498, 42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Sacramento, CA (July 2006), https://doi.org/10.2514/6.2006-4498

Goebel D., Wirz R.E., Katz I., “Analytical Ion Thruster Discharge Performance Model,” AIAA 2006-4486, 42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Sacramento, CA (July 2006) https://doi.org/10.2514/6.2006-4486

Katz I., Mikellides I., Goebel D., Jameson K., Wirz R.E., Johnson L., “Production of High Energy Ions Near an Ion Thruster Discharge Hollow Cathode,” AIAA-2006-4485, 42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Sacramento, CA (July 2006) https://doi.org/10.2514/6.2006-4485

Li Y., Hamlin L., Wirz R.E., Adams D., Moore G., Coppolino R., Peng C., Levine M., “Dynamic Simulations for the Terrestrial Planet Finder Interferometer,” Space Systems Optomechanics and Dynamics II, SPIE Conference, San Diego, CA (Aug. 2005) https://doi.org/10.1117/12.620012

Katz I., Mikellides I., Wirz R.E., J. Anderson, D. Goebel, “Ion Thruster Life Models,” AIAA-2005-4256, 41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Tucson, AZ (July 2005) https://doi.org/10.2514/6.2005-4256

Wirz R.E., Katz I., “Plasma Processes of DC Ion Thruster Discharge Chambers,” AIAA 2005-3690, 41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Tucson, AZ (July 2005) https://doi.org/10.2514/6.2005-3690

Wirz R.E., “Computational Modeling of a Miniature Ion Thruster Discharge,” AIAA-2005-3887, 41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Tucson, AZ (July 2005) https://doi.org/10.2514/6.2005-3887

Wirz R.E., Gale M., Mueller J., Marrese C., “Miniature ion thruster for precision formation flying,” AIAA 2004-4115, 40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Fort Lauderdale, FL (July 2004) https://doi.org/10.2514/6.2004-4115

Wirz R.E., Katz I., “2-D Discharge Chamber Model for Ion Thrusters,” AIAA-2004-4107, 40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Ft. Lauderdale, FL (July 2004) https://doi.org/10.2514/6.2004-4107

Brophy J., Anderson J., Beatty J., Goebel D., Goodfellow K., Johnson L., Katz I., Kolasinski R., Marrese C., Polk J., Sengupta A., Snyder S., Wirz R.E., “The Status of Ion Propulsion Development and Implementation at JPL in 2003,” AIAA 2003-4711, 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Huntsville, AL (July 2003) https://doi.org/10.2514/6.2003-4711

Wirz R.E., Katz I., “A Preliminary 2-D Computational Model of an Ion Thruster Discharge Chamber,” AIAA-2003-5163, 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Huntsville, AL (July 2003) https://doi.org/10.2514/6.2003-5163

Wirz R.E., Goebel D., Marrese C., Mueller J., “Development of Cathode Technologies for a Miniature Ion Thruster,” AIAA-2003-4722, 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Huntsville, AL (July 2003) https://doi.org/10.2514/6.2003-4722

Katz I., Anderson J., Goebel D., Wirz R.E., Sengupta A., “Plasma Generation Near an Ion Thruster Discharge Chamber Hollow Cathode,” AIAA 2003-5161, 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Huntsville, AL (July 2003) http://hdl.handle.net/2014/39043

Mueller J., Marrese C., Ziemer J., Green A., Yang E-H., Mojarradi M., Johnson T., White V., Bame D., Wirz R., Tajmar M., Hruby V., Gamero-Castano M., Schein J., Reinicke R., “JPL Micro-Thrust Propulsion Activities,” AIAA 2002-5714, NanoTech 2002, Houston, TX (Sept. 2002) https://doi.org/10.2514/6.2002-5714

Wirz R.E., Polk J., Marrese C., Mueller J., “Experimental and Computational Investigation of the Performance of a Micro-Ion Thruster,” AIAA-2002-3835, 38th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Indianapolis, IN (July 2002) https://doi.org/10.2514/6.2002-3835

Wirz R.E., Polk J., Marrese C., Mueller J., Escobedo J., Sheehan P. “Development and Testing of a 3cm Electron Bombardment Micro-Ion Thruster,” IEPC 01-343, 27th International Electric Propulsion Conference, Pasadena, CA (Jan. 2001) http://erps.spacegrant.org/uploads/images/images/iepc_articledownload_1988-2007/2001index/343_1.pdf

Conference Publications

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001