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• John E. Scharer
• Research Students
  1. Ryan Giar
  2. Yung-Ta Sung
  3. Matt Wiebold
  4. Xun Xiang
  5. Yan Li
  6. Previous Students
• Current Research
  1. Helicon Plasmas
  2. Laser Plasmas
  3. RF Plasmas
  4. Cold Cathodes
• Previous Research
  1. TWTs
  2. Fusion Plasmas
• Publications

Publications

• Y. T. Sung, Y. Li, J. E. Scharer. "Fast, hot electron production and ion acceleration in a helicon inductive plasma." Physics of Plasmas, 23 (092113), September 2016
• Y. T. Sung, Y. Li, J. E. Scharer. "Observation of warm, higher energy electrons transiting a double layer in a helicon plasma." Physics of Plasmas, 22 (034503), March 2015
• X. Xiang, B. Kupczyk, J. Booske, J. Scharer. "Diagnostics of fast formation of distributed plasma discharges using X-band microwaves." Journal of Applied Physics, 115 (063301), February 2014
• M. Wiebold, Y. T. Sung, J. E. Scharer. "Ion acceleration in a helicon source due to the self-bias effect." Physics of Plasmas, 19 (053503), May 2012
• M. Wiebold, Y. T. Sung, J. E. Scharer. "Experimental observation of ion beams in the Madison Helicon eXperiment." Physics of Plasmas, 18 (063501), June 2011
• R. Giar and J.E. Scharer. "Focused excimer laser initiated, radio frequency sustained high pressure air plasmas." Journal of Applied Physics, 110 (103301), Nov. 2011
• J. S. Hummelt, J. E. Scharer. "Excitational energy transfer enhancing ionization and spatial-temporal evolution of air breakdown with UV laser radiation." Journal of Applied Physics, 108 (093305), Nov. 2010
• M. Wiebold, H. Ren, J. E. Scharer, C. M. Denning. "Low Pressure Helicon Discharge Initiation Via Magnetic Field Ramping." IEEE Transactions on Plasma Sciences, 37 (2110-2115), Nov. 2009
• J. Way, J. Hummelt, J. E. Scharer. "Experimental measurements of multiphoton enhanced air breakdown by a subthreshold intensity excimer laser." Journal of Applied Physics, 106 (083303), Oct. 2009
• X. He, J. E. Scharer, J. Booske, S. Sengele. "One-dimensional combined field and thermionic emission model and comparison with experimental results." Journal of Vacuum Science and Technology, 26 (770-777), March 2008
• M. Thiyagarajan, J. E. Scharer. "Experimental Investigation of 193nm Laser Breakdown in Air." IEEE Plasma Sciences Special Issue on Pulsed Power, 36 (2512-2521), October 2008
• M. Thiyagarajan, J. E. Scharer. "Experimental Investigation of Ultraviolet Laser Induced Plasma Density and Temperature Evolution in Air." Journal of Applied Physics, 104 (013303), July 2008
• C. M. Denning, M. Wiebold, J. E. Scharer. "Observations of neutral depletion and plasma acceleration in a flowing high-power argon helicon plasma." Physics of Plasmas, 15 (072115), July 2008
• S. Luo, C. M. Denning, J. E. Scharer. "Laser-rf creation and diagnostics of seeded atmospheric pressure air and nitrogen plasmas." Journal of Applied Physics, 104 (13301), July 2008
• X. He, J. E. Scharer, J. Booske, S. Sengele, V. Vlahos, N. Jordan, R. Gilgenbach. "High Current Density Cathode Facility." Poster Presentation, IEEE International Vacuum Electronics Conference (Kitakyush, Japan), 2007
• J.E. Scharer. "Laser and RF Plasma Source and Diagnostic Additions." DURIP Final Report, (FA9550-06-1-0285), April 2007
• S. Luo, J. E. Scharer, M. Thiyagarajan, and C. M. Denning. "Experimental Study of Laser-Initiated Radiofrequency-Sustained High-Pressure Plasmas." IEEE Transactions on Plasma Science, 34 (2637), December 2006
• A. Singh, J. E. Scharer, J. Booske, and J. Wohlbier. "Second- and Third-Order Signal Predistortion for Nonlinear Distortion Suppression in a TWT." IEEE Transactions on Electron Devices, 52 (709-716), May 2005
• A. Singh, J. Wohlbier, J. Booske, and J. E. Scharer. "Experimental verification of the mechanisms for nonlinear harmonic growth and suppression by harmonic injection in a traveling wave tube ." Physical Review Letters, 20 (205005), May 2004
• K. Akhtar, J. E. Scharer, S. Tysk, and C. M. Denning. "Characterization of laser produced tetrakis (dimethylamino) ethylene plasma in a high-pressure background gas ." IEEE Transactions on Plasma Sciences, 32 (813-822), April 2004
• S. M. Tysk, C. M. Denning, J. E. Scharer, and K. Akhtar. "Optical, wave measurements, and modeling of helicon plasmas for a wide range of magnetic fields." Physics of Plasmas, 11 (878-887), March 2004
• S. M. Tysk, C. M. Denning, J. E. Scharer, B. O. White, and K. Akhtar . "Experimental measurements and modeling of a helicon plasma source with large axial density gradients." American Institute of Physics, 15th Topical Conference on Radio Frequency Power , CP694 (427-430), May 2003
• K. Akhtar, J. E. Scharer, S. M. Tysk, and C. M. Denning. "Plasma interferometry at high pressures." Review of Scientific Instruments, 74 (996-1001), February 2003
• J. E. Scharer, A. Degeling, G. Borg, and R. Boswell . "Measurements of helicon wave propagation and Ar II emission." Physics of Plasmas, 9 (3734-3742), September 2002
• K. L. Kelly, J. E. Scharer, E. S. Paller, and G. Ding. "Laser Ionization and Radiofrequency Sustainment of High-Pressure Seeded Plasmas." Journal of Applied Physics, 92 (698-708), July 2002
• M. Wirth, A. Singh, J. E. Scharer and J. Booske. "Third Order Intermodulation Reduction by Harmonic Injection in a TWT Amplifier." IEEE Transactions on Electron Devices, 49 (1082-1084), June 2002
• G. Ding, J. E. Scharer and K. Kelly. "Diagnostics and Analyses of Decay Processes in Laser Produced Tetrakis(dimehty-amino) Ethylene Plasma." Physics of Plasmas, 8 (334-342), January 2001
• E. S. Paller, J. E. Scharer, K. Akhtar, K. Kelly, G. Ding. "Radiofrequency Initiation and Radiofrequency Sustainment of Laser Initiated Seeded High Pressure Plasmas." Radio Frequency Power in Plasmas, (526-529), 2001
• X. Guo, J. E. Scharer, Y. Mouzouris and L. Louis. "Helicon Experiments and Simulations in Nonuniform Magnetic Field." Physics of Plasmas, 6 (3400-3407), August 1999
• K. L. Kelly, J. E. Scharer, G. Ding, M. Bettenhausen, and S. P. Kuo. "Microware reflections from an Ultra-violet Laser Produced Plasma Sheet." Journal of Applied Physics, 85 (63-68), January 1999
• Y. Mouzouris and J. E. Scharer. "Wave Propagation and Absorption Simulations for Helicon Sources." Physics of Plasmas, 5 (4253-4260 ), December 1998
• G. Ding, J. E. Scharer and K. Kelly. "Effects of rapidly decaying plasmas on Langmuir probe measurements." Journal of Applied Physics, 84 (1236-1240), August 1998
• W. Shen, J. E. Scharer, B. Porter, N. Lam, and K. Kelly. "Properties of an Ultraviolet Laser Created Plasma Sheet for a Microwave Reflector ." Journal of Applied Physics, 78 (6974), December 1995
• J. E. Scharer, O. Eldridge, S. Chang, Y Zhang, M. Bettenhausen and N. Lam. "Electron Cyclotron Wave Propagation, Absorption and Backscatter Measurements in a Laboratory Plasma." IEEE Transactions on Plasma Sciences, 21 (271-281), June 1993
• Y. S. Zhang and J. E. Scharer . "Plasma Generation in an Organic Molecular Gas by an Ultraviolet Laser Pulse." Journal of Applied Physics, 73 (4779), May 1993
• J. E. Scharer, J. Jacquinot, P. Lallia and F. Sand. "Fokker-Planck Calculations for JET ICRF Heating Scenarios." Nuclear Fusion, 25 (435), 1985

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Site last updated: October 23, 2016

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