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| WALTER GEKELMAN
At UCLA Gekelman has developed three different plasma devices, each becoming progressively larger and more sophisticated technologically to solve problems at the frontier of basic plasma research. The first device, named SCAMP (Source Chamber and Magnetized Plasma) was utilized to make the first measurement of the linear dispersion relation of lower-hybrid waves, and the discovery of nonlinear effects associated with the ponderomotive force of the related resonance cones. The device was also used to study the turbulence that develops when a current flows through a collisionless plasma and resulted in the first experiment to illustrate the three dimensional nature of ion-acoustic turbulence and the scattering it produces on test particles. The next device, built jointly by Gekelman and Prof. R. Stenzel, required the development of a one-meter oxide cathode to generate a large volume plasma. An intensive effort spanning several years led to the most comprehensive laboratory study of reconnection processes and the first observation of tearing of a current sheet. The results were reported in several publications that are extensively quoted by experts in the reconnection area. Gekelman obtained substantial extramural and university resources and over a period of 4.5 years led a team of undergraduate and graduate students in the construction of the Large Plasma Device (LAPD). This is widely perceived as the premier machine for basic plasma studies and is presently yielding important insight into basic processes observed in space by rockets and spacecraft. In 1997 this effort culminated in an MRI award by the NSF in which Gekelman was PI. The device will completed in the Early Spring of 2001, and is expected to become a National User Facility for basic Plasma Research. During the reconnection phase of his research Gekelman pioneered the use of computer visualization techniques in plasma physics in order to elucidate the complex three dimensional structures that are hidden in very large data sets. This has been a topic of great interest to Gekelman and he has lead various efforts in this area including the development of a visualization center at UCLA. He is presently co-PI in a NSF-sponsored interdisciplinary project to develop real-time analysis of complicated data sets. Gekelman has published several papers in this area including an educational CD-ROM entitled "Relativistic City" in which the subtleties of special relativity are illustrated. As coordinator for computing Gekelman was responsible for laying the early foundations for effective computation in the physical sciences at UCLA. In this capacity Gekelman developed extensive contacts with industrial partners and secured significant computing resources for UCLA. Gekelman has deep interest in improving the level of science education and is leading various efforts in this area. The most significant is the creation in 1993 of the LAPTAG outreach project involving high school teachers and students in thirty two institutions in the Los Angeles basin. Gekelman participates in various groups charting new directions in this area. Walter Gekelman has been a consultant for TRW and SAIC and has served on NASA and DOE panels.
Significant publications: Y. Zhang, W. W. Heidbrink, H Boehmer, R. McWilliams, G. Chen, S. Vincena, T. Carter, D. Leneman, W. Gekelman, P. Pribyl, and B. Brugman, Spectral gap of shear Alfvén waves in a periodic array of magnetic mirrors , Phys. Plasmas, v15, 012103, (2008). D. Leneman, Reflection of Alfvén waves from boundaries with different conductivities, Phys. Plasmas, v14, 122109, (2007). B. Jacobs, W. Gekelman, P. Pribyl, M. Barnes, and M. Kilgore, Laser-induced fluorescence measurements in an inductively coupled plasma reactor, App. Phys. Lett., 91 161505, (2007.) Y. Zhang, H. Boehmer, W. W. Heidbrink, R. McWilliams, D. Leneman, and S. Vincena, Lithium ion sources for investigations of fast ion transport in magnetized plasmas, Rev. Sci. Instrum, 78, 013302 (2007). W. Gekelman, A. Collette, and S. Vincena , Three-dimensional current systems generated by plasmas colldiing in a background magnetoplasma , Phys. Plasmas, 14, 062109 (2007). J.E. Maggs, T.A. Carter, and R.J. Taylor, Transition from Bohm to classical diffusion due to edge rotation of a cylindrical plasma, Phys. Plasmas, 14, 052507 (2007). F.S. Tsung, G.J. Morales, and J. Tonge, Alfvénic phenomena triggered by resonant absorption of an O-mode pulse, Phys. Plasmas, 14, 042101, 2007. W. Gekelman, J. Wise, P. Pribyl, R. Baker, W. Layton, J. Skrzypek, P. Niknejadi, R. Ransom, D. Lee, R. Zarinshesnas, T. Kim, R. Buck, E. Warfel, T. Tasoff, J. Carmona, S. Skolnik, L. Kim, D. Furlong, and N. Gibson, Ion acoustic wave experiments in a high school plasma physics laboratory, Am. J. Phys. 75 (2) 2007. Y. Zhang, H. Boehmer, W.W. Heidbrink, R. McWilliams, D. Leneman, and S. Vincena, Lithium ion sources for investigations of fast ion transport in magnetized plasma, Rev. Sci. Instrum., 78, 013302, 2007. V.A. Manasson, A. Avakian, A. Brailovsky, W. Gekelman, A. Gigliotti, L. Giubbolinni, I. Gordion, M. Felman, V. Khodos, V. Litvinov, P. Pribyl, L. Sadovnik, Time/Space-Probing Interferometer for Plasma Diagnostics, Proceedings of the 2006 Antenna Applications Symposium, Allerton Park, Monticello, Illinois, Sept 20-22, 2006
S. Vincena and W. Gekelman, Drift-Alfven wave mediated particle transport in an elongated density depression, Physics of Plasmas, vol.13, no.6, June 2006,pp. 64503-1-4 G. J. Morales and J. E. Maggs, Differential equation model of an Alfvén wave maser, Phys. Plasmas 13, 052109 (2006) (13 pages) T.A. Carter, B. Brugman, P. Pribyl, and W. Lybarger, Laboratory Observation of a Nonlinear Interaction between Shear Alfven Waves, Phys. Rev. Lett., 96, 155001, 2006. D. Leneman, W. Gekelman, and J. Maggs, The plasma source of the Large Plasma Device at University of California, Los Angeles, Rev. Sci. Instrum., 77, 015108 , 2006 T.A. Carter, Intermittent turbulence and turbulent structures in a linear magnetized plasma, Phys. Plasmas, 13, 010701-1 , 2006 B. Van Compernolle, W. Gekelman and P. Pribyl, Generation of suprathermal electrons and Alfvén waves by a high power pulse at the electron plasma frequency, Physics of Plasmas, vol 13, 092112, 2006. B. Van Compernolle, W. Gekelman, P. Pribyl, T. Carter, Generation of Alfvén waves by a high power pulse at the electron plasma frequency, Geo. Phys. Res. Letts. , 32, L08101, 2005 N. Palmer, W. Gekelman, and S. Vincena, Measurement of Ion Motion in a Shear Alfvén Wave, Phys. Plasmas 12, 072102 (2005). L. Zhao, W. W. Heidbrink, H. Boehmer, R. McWilliams, D. Leneman, and S. Vincena, Measurements of classical transport of fast ions, Phys. Plasmas 12, 052108 (2005). S. Vincena and W. Gekelman, Visualizing shear Alfvén wave currents near the ion-cyclotron frequency, IEEE Trans. Plasma Sci., pp 552, v33, n2, (2005). W. Gekelman and S. Vincena, Imaging complex three-dimensional Alfvén wave currents, Phys. Plasmas, IEEE Trans. Plasma Sci., pp 546, v33, n2, (2005). W. Horton, J. Perez, T. Carter, and R. Bengtson, Vorticity probes and the characterization of vortices in the Kelvin-Helmholtz instability in the large plasma device experiment, Phys. Plasmas, v12, n2, (2005). J. Maggs, G. Morales, and T. Carter, An Alfvén wave maser in the laboratory, Phys. Plasmas, v12, n1, (2005). Tsung FS, Tonge JW, Morales GJ., Particle simulation of Alfven waves excited at a boundary, Physics of Plasmas, vol.12, no.1, Jan. 2005, pp. 12508-1-11 S. Vincena, W. Gekelman, and J. Maggs, Shear Alfvén wave perpendicular propagation from the kinetic to the inertial regime, Phys. Rev. Lett, v93 n10, 2004. Experimental verification of the zero perpendicular group velocity turning point for Alfvén waves with a parallel phase speed near the electron thermal speed. H. Boehmer, D. Edrich, W. Heidbrink, R. McWilliams, L. Zhao, and D. Leneman, Operation of a 0.2-1.1 keV ion source within a magnetized laboratory plasma, Rev. Sci. Instr., v75, n4, (2004). P. Pribyl and W. Gekelman, 24kA solid state switch for plasma discharge experiments, Rev. Sci. Instr., v75, n3, (2004). R. Boswell, Cosmic Waves in the Lab, Nature, 25, 352, (2003) {review of the Alfvén wave maser} Tsung FS, Morales GJ, Leboeuf JN. Dynamics of a supersonic plume moving along a magnetized plasma, Physical Review Letters, vol.90, no.5, 7 Feb. 2003, pp. 0550041-4 Morales GJ, Tsung FS, Leboeuf JN. Dynamics of a supersonic plume moving along a magnetized plasma. AIP Conference Proceedings, no.669, 2003, pp. 749-5 W. Gekelman, M. Van Zeeland, S. Vincena, P. Pribyl, Laboratory Experiments of Alfvén waves caused by rapidly expanding plasmas and their relationship to space phenomena, J. Geophys. Res. 108, SMP-8-1 (2003) J. Maggs and G. Morales, Magnetic fluctuations of a large nonuniform plasma column, Phys. Plasmas, v10, n6, (2003). J. Maggs and G. Morales, Laboratory realization of an Alfvén wave maser, Phys. Rev. Lett., v91, n3, (2003). C. Kletzing, S. Bounds, J. Martin-Hiner, W. Gekelman, C. Mitchell, Measurements of the shear Alfven wave dispersion for finite perpendiular wave number, Phys. Rev. Lett, 90 (2003). A novel antenna is used to launch Alfven waves with small perpendicular (to B ) wavelengths. M. Van Zeeland, W. Gekelman, S. Vincena, J. Maggs, Currents and shear Alfven radiation generated by an expanding laser-produced plasma: perpendicular incidence , Phys. Plasmas, 10, 1243, (2003) W. Gekelman, LAPTAG- A Physics Outreach Program at UCLA, APS news Oct (2002) C. Mitchell, J. Maggs, W. Gekelman, Field line resonances in a cylindrical Plasma, Phys. Plasmas, 9, 2909, (2002). Experiment on Alfven field line resonances and comparison with theory. S. Rosenberg, W. Gekelman, A three dimensional experimental study of lower hybrid wave interactions with field aligned density depletions, Jour. Geophys. Res., 106, 28,867 (2001). Experimental study of an ionospheric phenomena D, Leneman, W. Gekelman, A novel angular motion feedthrough, Rev. Sci. Instrum, 72, 3473, (2001) S. Vincena, W. Gekelman, and J. Maggs, Shear Alfvén waves in a magnetic beach and the roles of electron and ion damping. Phys. Plasmas, v8, n9, Sept., 2001. M. VanZeeland, W.Gekelman, S. Vincena, and G. Dimonte, Production of Alfvén Waves by a Rapidly Expanding Dense Plasma, Phys. Rev. Lett., 2001. T. Drozdenko, G.J. Morales, Effect of Cross Field Flow on inertial Alfvén waves of small transverse scale length, Phys. Plasmas, 8, 3177, (2001) T. Drozdenko, G.J. Morales, Nonlinear effects resulting from the interaction of large-scale Alfvén wave with a density filament, Phys. Plasmas, 8, 3265 (2001) Mitchell, C.; Vincena, S.; Maggs, J.; Gekelman, W. Laboratory observation of Alfvén resonance. Geophysical Research Letters, vol.28, (no.5), American Geophys. Union, 1 March 2001. p.923-6. S. Rosenberg and W.Gekelman, A three-dimensional experimental study of lower hybrid wave interactions with field-aligned density depletion.Geophys. Res. Lett, 27, 859-862 (2000) Experimental Measurements of Large Amplitude Shear Waves and corresponding density perturbations, includes LIF measurements. W.Gekelman, S. Vincena, N. Palmer, P. Pribyl, D. Leneman, C. Mitchell, J. Maggs, Experimental Measurements of the Propagation of large-amplitude shear Alfvén waves, Plasma Phys. Control. Fusion, 42, B15-B26 (2000) T. Drozdenko, G.J. Morales, Interaction of a Shear Alfvén wave with a filamentary density perturbation in a low beta plasma, Phys. Plasmas, 7, 823, (2000) Burke AT, Maggs JE, Morales GJ. Experimental study of fluctuations excited by a narrow temperature filament in a magnetized plasma. [Journal Paper] Physics of Plasmas, vol.7, no.5, May 2000, pp. 1397-407 Burke AT, Maggs JE, Morales GJ. Experimental study of classical heat transport in a magnetized plasma. [Journal Paper] Physics of Plasmas, vol.7, no.2, Feb. 2000, pp. 544-53. Study of Fluctuations that spontaneously develop in a skin depth size temperature filament, A.T. Burke, J. Maggs, G. Morales, Spontaneous Fluctuations of a Temperature Filament in a Magnetized Plasma, Phys. Rev. Lett., 84, 1451 (2000) Penano JR, Morales GJ, Maggs JE. Drift-Alfvén fluctuations associated with a narrow pressure striation. [Journal Paper] Physics of Plasmas, vol.7, no.1, Jan. 2000, pp. 144-57 Observations of kinetic and inertial shear Alfvén waves: D. Leneman, W. Gekelman, and J. Maggs, Laboratory Observations of Shear Alfvén Waves Launched from a Small Source, Phys. Rev. Letters, 82, 2673-2676 (1999). A review paper on Alfvén wave experiments over the years: W. Gekelman, Review of laboratory experiments on Alfvén waves and their relationship to space observations, Jour. Geophys. Res., 104,14,14,417-14,435 (1999) S. Vincena, W. Gekelman, 3D Observations of Electromagnetic Ion Cyclotron Wave Propagation in a Laboratory Plasma Column,Ú IEEE Transactions on Plasma Science, 27 (1) ,1999 An atomic model for a helium d.c. discharge using the Los Alamos suite of atomic physics codes was used to calculate the density and temperature in the LAPD device. The results were compared with experimental data in: J. Abdalllah Jr., N. Palmer, W. Gekelman, J. Maggs, and R.E.H. Clark, Time-dependent kinetics model for a helium discharge plasma, J. Phys. B: At. Mol. Opt. Phys. 32 1001-1008 (1999) Morales GJ, Maggs JE, Burke AT, Penano JR. Alfvenic turbulence associated with density and temperature filaments. [Conference Paper; Journal Paper] IOP Publishing. Plasma Physics and Controlled Fusion, vol.41, suppl.3A, March 1999, pp. A519-29. UK. Using military flight simulation techniques to view large plasma physics data sets: C. Mitchell, W. Gekelman, Real-time physics data-visualization system using Performer, Computers in Physics 12, 371 Jul/Aug 1998 Measurement of the electric field of whistler and lower hybrid waves at a density striation: S. Rosenberg, W.Gekelman, Electric Field Measurements of directly converted lower hybrid waves at a density striation, Geophys. Res. Letts., 25, 865 (1998) A.T. Burke, J.E. Maggs and G.J. Morales, Observation of Simultaneous Axial and Transverse Classical Heat Transport in a Magnetized Plasma, Phys. Rev. Letters, 81, 3659 (1998) A thorough review of the properties of Alfvén wave cones in the context of space plasmas illustrating their three dimensional propagation and interference effects has been published and may be downloaded. W. Gekelman, S. Vincena, D. Leneman, J. Maggs, Laboratory Experiments on shear Alfvén waves and their relationship to space plasmas, Jour. of Geophys. Res., 102, 7225-7236 (1997) Morales GJ, Maggs JE. Structure of kinetic Alfven waves with small transverse scale length, Physics of Plasmas, vol.4, no.11, Nov. 1997, pp. 4118-25 Maggs JE, Morales GJ, Gekelman W., Laboratory studies of field-aligned density striations and their relationship to auroral processes, Physics of Plasmas, vol.4, no.5, pt.2, May 1997, pp. 1881-8 Penano JR, Morales GJ, Maggs JE. Properties of drift waves in a filamentary density depletion, Physics of Plasmas, vol.4, no.3, March 1997, pp. 555-65 The three dimensional current structure of Alfvén wave cones is presented in: W. Gekelman, S. Vincena, D. Leneman, Experimental Observations of Shear Alfvén waves generated by narrow current channels, Plasma Phys. and Control. Fusion, 39, A101-A112 (1997) Maggs JE, Morales GJ. Fluctuations associated with a filamentary density depletion, Physics of Plasmas, vol.4, no.2, Feb. 1997, pp. 290-9 Maggs JE, Morales GJ. Magnetic fluctuations associated with field-aligned striations. [Journal Paper] Geophysical Research Letters, vol.23, no.6, 15 March 1996, pp. 633-6. Publisher: American Geophys. Union, USA. Laboratory study of the interaction of a whistler wave with a density striation showing its direct conversion to lower-hybrid waves: J.F. Bamber, J.E. Maggs, and W. Gekelman, Whistler Wave Interaction with a Density Striation: A Laboratory Investigation of an Auroral Process, Jour. of Geophys. Res., 100, 23795-23810 (1995) Morales GJ, Loritsch RS, Maggs JE. Properties of Alfven waves with transverse scale on the order of the skin-depth. [Conference Paper] 1994 International Conference on Plasma Physics. Joint Conference of the 10th Kiev International Conference on Plasma Theory, 10th International Congress on Waves and Instabilities in Plasmas, Combined with 6th Latin American Workshop on Plasma Physics. Proceedings . INPE. Part vol.3, 1994, pp. 189-92 vol.3. Sao Jose des Campos, Brazil. Morales GJ, Loritsch RS, Maggs JE., Structure of Alfven waves at the skin-depth scale, Physics of Plasmas, vol.1, no.12, Dec. 1994, pp. 3765-74. W. Gekelman, D. Leneman, J. Maggs, S. Vincena, Experimental Observation of Alfven wave cones, Phys. Plasmas, 1, 3775 (1994). Alfven waves geberated by narrow, fluctuating current channels. Srivastava S, Morales GJ, Maggs JE., Nonlinear Landau damping of resonantly excited fields in nonuniform plasmas, Physics of Plasmas, vol.1, no.3, March 1994, pp. 567-78. M. VanZeeland, W. Gekelman,Laser-Plasma Diamagnetism in the presence of an Ambient Magnetized Plasma, Phys. Plasmas, 11, 320-323 (2004) 3 pages W. Gekelman, Comment on Properties of Lower Hybrid Solitary Structures: A Comparison between space observations, a laboratory experiment and the cold homogeneous plasma dispersion relation by Shuck et al, J. Geophys. Res, 109, A01311, (2004) 6 pages D. Leneman, W. Gekelman, J. Maggs, Shear Alfvén Wave Radiation from a Source with Small Transverse Scale Length, Physics of Plasmas, 7, 3934, (2000) W. Gekelman, S. Vincena, D. Leneman, S. Rosenberg, A. Burke, Laboratory Investigation of Structure in Plasmas, Phys. of Space Plasmas, 15, 109-113, (1998) 4 pages C. Mitchell, W. Gekelman, The Virtual Plasma Physics World Data Visualization System, Computers in Physics, 12, 371-379 (1998) 8 pages L. Mandrake, W. Gekelman, Large-Scale Windows 95 Data Acquisition System using LabView, Computers in Physics, 11, 5-20, (Sept/Oct 1997) 15 pages W. Gekelman, S. Vincena, D. Leneman, Experimental Observations of Shear Alfvén Waves Generated by Narrow Current Channels, Plasma Physics and Controlled Fusion, 39, 101-112 (1997) 11 pages J. E. Maggs, G. J. Morales, W. Gekelman, Laboratory studies of field-aligned density striations and their relationship to Auroral processes, Physics of Plasmas, 4, 1881-1888 (1997) 7 pages W. Gekelman, S. Vincena, D. Leneman, J. Maggs, Laboratory Experiments on Shear Alfvén Waves and their relationship to Space Plasmas, Journal of Geophysical Research, 102, 7225-7236 (1997) 11 pages G. Morales, W. Gekelman, Third International Workshop on Interrelations Between Plasma Experiments in the Laboratory and in Space, Comments Plasma Phys. Controlled Fusion, 17, 185-193 (1996) 8 pages W. Gekelmam, J. Maggs, J. Bamber, S. Vincena, A Whistler Wave Interaction with a Density Striation, IEEE Transactions on Plasma Science, 24, 20 & 21 (1996) 2 pages B. Eyre, K. Pister, W. Gekelman, Multi-Axis Micro-Coil Sensors in Standard CMOS, Proceedings SPIE 1995 Symposium on Micromaching and Mmicrofabrication, Austin, Texas (1995) 4 pages J.F. Bamber, W. Gekelman, J.E. Maggs, Observation of Whistler Wave Mode Conversion to Lower Hybrid Waves at a Density Striation, Physical Review Letters, 73, 2990 – 2993 (1994) 3 pages W. Gekelman, IAGA Reporter Review on Laboratory and Active Experiments, 1993, Surveys in Geophysics, special issue: Progress in Magnetospheric Physics, Vol 16, 1991-1993; IAGA Division III Reporter Reviews presented at the 7th Scientific Assembly, Buenos Aires, Argentina, 458-485, (August 1993), Editor S.W. H. Cowley, Kluwer Acad. Press, the Netherlands. 34 pages W. Gekelman, J., Bamber, D. Leneman, S. Vincena, J. Maggs, S. Rosenberg, Making Sense from Space-Time Data in Laboratory Experiments on Space Plasma Processes, Visualization Techniques in Space and Atmospheric Sciences, Ed. E.P. Szuszczewicz, J.H. Bredekamp, NASA Publication SP-519 (1995) 11 pages W. Gekelman, J. Maggs, H. Pfister, Experiments on the Interaction of Current Channels in a Laboratory Plasma: Relaxation to a Force Free State, IEEE Transactions on Plasma Science, 20, 614-621 (1992) W. Gkelman, Data Acquisition Systems, Encyclopedia of Applied Physics, Vol. 4, 463-483, VCH Publishing Co., (1992) 20 pages H. Pfister, W. Gekelman, J. Bamber, D. Leneman, Z, Lucky, A Fully 3D-movable, 10m Long, Remotely Controlable Probe Drive for a Plasma Discharge Device, PPG-1355, Rev. of Scientific Instrum., 62, 2884-2889, (May 1991) 5 pages W. Gekelman, H. Pfister, Z. Lucky, J. Bamber, D. Leneman, J. Maggs, Design, Construction and Properties of the Large Plasma Research Device – The LAPD at UCLA, Rev. Scientific Instrum., 62, 2875-2883 (1991) 8 pages W. Gekelman, James Maggs, Real Time Relativity, Computers in Physics, 5, 372-385, July/Aug (1991) 13 pages R. L. Stenzel, J.M. Urrutia, W. Gekelman, H. Pfister, Laboratory Experiments on Magnetic Reconnection and Current Systems, Adv, Space Res., 10, pp. 955-971, (1990) 16 pages W. Gekelman, H. Pfister, J.R. Kan, Experimental Observations of Patchy Reconnection Associated with the Three-Dimenional Tearing Instability, Jour. of Geophys. Research, 96, 3829-3833, October (1991) 5 pages H. Pfister, W. Gekelman, Demonstration of Helicity Conservation during Magnetic Reconnection with Christmas Ribbons, Am J. of Phys, 59, 497-502, June (1991) 5 pages W. Gekelman, H. Pfister, R.L. Stenzel, J. Bamber, Dynamics of Current Channels with Large Self-Generated Magnetic Fields, in Turbulence and Nonlinear Dynamics in MHD Flows, p. 147-163, Proceedings of Workshop in Cargese, France, July 4-8, 1988, Ed. M. Meneguzzi, et al., Elsevier Press, (North Holland) (1989) 17 pages W. Gekelman, H. Pfister, R.L. Stenzel, Observation of the Electron Tearing Mode in an Electron Current Sheet, in Procedings of the Chapman Conference on Plasma Waves and Instabilities in Magnetopheres and Comets, Sendai/Mt. Zao, Japan, Octoboer 12-16, 1987, pp. 125-128, Sohbun Insatsu Co. (1987) 4 pages W. Gekelman, H. Pfister, Experimental Observations of the Tearing of an Electron Current Sheet, Phys. of Fluids, 31, 2017 (1988) 9 pages R. L. Stenzel, W. Gekelman, J.M. Urrutia, Lessons from Laboratory Experiments on Reconnection, Adv. Space Res. 6, 135 (1986) 7 pages W. Gekelman, L. Xu, A Flexible, Real Time, Data Collection and Analysis System and Its Utilization in a Basic Plasma Physics Experiment, Rev. Sci. Instr. 57, 1851-1856, (1986) 5 pages R. L. Stenzel, W. Gekelman, J.M. Urrutia, Laboratory Experiments on Magnetic Reconnection and Current Disruptions, in Comparative Study of Magnetospheric Systems, La Londe-Les-Maures, France, September 1985, pp. 297-306, CEPAD, Toulouse, France, (1986) 9 pages W. Gekelman, J. M. Urrutia, R. L. Stenzel, Measurement of Magnetic Helicity During the Disruption of a Neutral Current Sheet, in Magnetotail Physics, Ed. A..T. Lui, Baltimore: John Hopkins Press (1987) pp. 261-274. 13 pages R. L. Stenzel. W. Gekelman, J. M. Urrutia, Laboratory Experiments on Magnetic Reconnection and Turbulence, in Magnetic Reconnection and Turbulence, pp. 63-77, M.A. DuBois, D. Gresillon, M.N. Bussac, editors, Les Editions de Physique, Palaiseau, France, (1985) 15 pages. W. Gekelman, R.L. Stenzel, Measurement and Instability Analysis of 3-Dimensional Anisotropic Electron Distribution Functions, Phys. Rev. Let. 54, 2414 (1985) 4 pages R. L. Stenzel, W. Gekelman, Laboratory Experiments on Current Sheet Disruptions, Double Layers, Turbulence and Reconnection, Proceedings of the International Astronomical Union Symposium No. 107 on Unstable Current Systems and Plasma Instabilities in Astrophysics, 47-60, College Park, MD, D. Reidel Publ. Co,., (1985) 2 pages R. L. Stenzel, W. Gekelman, Particle Acceleration During Reconnection in Laboratory Plasmas, Adv. Space Res. Vol. 4, pp. 459-470 (1984) 11 pages R. L. Stenzel, W. Gekelman, Laboratory Experiments on Magnetic Field Line Reconnection, J. Belcher, H. Bridge, T. Chang, B. Coppi, J.R. Jasperse, Editors, pp. 229-241, Scientific Publ., Inc., Cambridge, MA (1984) 12 pages W. Gekelman, R. L. Stenzel, Laboratory Experiments on Current Sheet Disruptions, reprinted from Magnetic Reconnection in Space and Laboratory Plasmas, Geophysical Monograph 30 Pub. Amer. Geo. Union (1984) 2 pages R. L. Stenzel, W. Gekelman, Nonlinear Interactions During Magnetic Field Line Reconnection in Plasmas, Physica 12D, 133-144 (1984) 13 pages W. Gekelman, R. L. Stenzel, Magnetic Field Line Reconnection Experiments, Part 6 Magnetic Turbulence, J. Geophys. Res. 89, 2715-2733 (1984) 19 pages R. L. Stenzel, W. Gekelman, N. Wild, J.M. Urrutia, D. Whelan, Directional Velocity Analyzer for Measuring Electron Distribution Functions in Plasmas, Rev. Sci. Instrum. 54, 1302-1310 (1983) 9 pages R.L. Stenzel, W. Gekelman, N. Wild, “Reply,” J. Geophys. Res. 88, 507-508 (1983) 2 pages N. Wild, R.L. Stenzel, W. Gekelman, Experimental Modeling of Satellite Wakes in Auroral Arcs, Geophys. Res. Lett. 10, 682-685 (1983) 4 pages N. Wild, R. L. Stenzel, W. Gekelman, Electron Temperature Measurements in a 12-Channel Array Probe, Rev. Sci. Instrum. 54, 935-939 (1983) 5 pages R. L. Stenzel, W., Gekelman, N. Wild, Electron Distribution Functions in a Current Sheet, Physics of Fluids, 26, 1949-1952 (1983) 3 pages R.L. Stenzel, W. Gekelman, N. Wild, Magnetic Field Line Reconnection Experiments. 5. Current Disruptions and Double Layers, J. Geophys. Res. 88, 4793 (1983) 12 pages R. L. Stenzel, W. Gekelman, N. Wild, Double Layer Formation During Current Sheet Disruptions in a Reconnection Experiment, Jour. Geophys. Res., Letters, 9, 680-683 (1982) 4 pages R. L. Stenzel, W. Gekelman, N. Wild, Double Layer Formation During Current Sheet Disruptions in a Reconnection Experiment, Symposium on Plasma Double Layers, Rio National Laboratory, Roskilde, Denmark, Risd-R-472, 181-186 (1982) 6 pages W. Gekelman, R. L. Stenzel, N. Wild, Magnetic Field Line Reconnection Experiments, Physica Scripta T2:2, 277-287 (1982) 11 pages R. L. Stenzel, W. Gekelman, Laboratory Experiments on Magnetic Field Line Reconnection, in Proceedings of the XVth International Conference on Phenomena in Ionized Gases, 1981, Part III, Invited Papers, Minsk, U.S.S.R., pp. 46-59, (1981) 14 pages R. L. Stenzel, W. Gekelman, N. Wild, Magnetic Field Line Reconnection Experiment, in Relation Between Laboratory and Space Plasmas, H. Kikuchi, editor, Reidel Publishing Company, Dordrecht, Holland, pp. 145-155, (1981) 10 pages R. L. Stenzel, W. Gekelman, N. Wild, Magnetic Field Line Reconnection Experiments. 4. Resistivity, Heating and Energy Flow, Jour. Geophys. Res. 87 111-117 (1982) 7 pages W. Gekelman, N. Wild, Magnetic Field Line Reconnection Experiments. 3. Ion Acceleration, Flows and Anomalous Scattering, Jour. Geophys. Res. 87, 101-110 (1982) 10 pages R. L. Stenzel, W. Gekelman, N. Wild, Laboratory Experiments on Magnetic Field Line Reconnection, in Physics of Auroral Arc Formation, A.I. Akasofu and J. R. Kan, Editors, Geophysical Monograph 25, 398-407 (1981) 10 pages N. Wild, W. Gekelman, R. L. Stenzel, Resistivity and Energy Flow in a Plasma Undergoing Magnetic Field Line Reconnection, Phys. Rev. Lett. 46. 339-342 (1981) 4 pages R. L. Stenzel, W. Gekelman, Magnetic Field Line Reconnection Experiments. 2. Plasma Parameters, Jour. Georphys. Res. 86, 659-666 (1981) 8 pages R. L. Stenzel, W. Gekelman, Magnetic Field Line Reconnection Experiments. 1. Field Topologies, Jour. Geophys. Res. 86, 649-658 (1981) 10 pages B. H. Quon, W.F. DiVergilio, W. Gekelman, Z. Guiragossian, R. L. Stenzel, Generation of Strong Time Compressed Light Ion Beams, Jour. Appl. Phys. 52, 5414-5418 (1981) 5 pages V. Vanek, D.P. Dixon, W. Gekelman, Production of Negative Ions in an Alkali Hydride Arc, Jour. Appl. Phys. 50, 7237-7239 (1979) 3 pages R. L. Stenzel, W. Gekelman, Experiments on Magnetic Field Line Reconnection, Phys. Rev. Lett. 42, 1055-1057 (1979) 3 pages R. L. Stenzel, W. Gekelman, Dynamics of Test Particles in a Turbulent Magnetoplasma, Phys. Fluids 21, 2024-2031 (1978) 8 pages W. Gekelam, R. L. Stenzel, Ion Sound Turbulence in a Magnetoplasma, Phys. Fluids, 21, 2014-2023 (1978) 10 pages W. Gekelman, V. Vanek, A.Y. Wong, Characterization of a Laser Produced Negative-Hydrogen Ion Plasma, Jour. Appl. Phys. 49, 3049-3058 (1978) 10 pages R. L. Stenzel, W. Gekelman, Diffusion and Scattering of Test Particles in a Turbulent Plasma, Phys. Rev. Lett., 40, 550-553 (1978) 4 pages V. Vanek, W. Gekelman, A.Y. Wong, Negative Hydrogen and Deuterium Ion Production by a Laser Irradiation of Alkali Hydride/Deuteride Targets, Proceedings of Symposium on the Production and Neutralization of Negative Hydrogen Ion Beams, Brookhaven, New York, 315-321 (1977) 7 pages. J. Ickovic, R. L. Stenzel, W. Gekelman, Direct Density Display with a Resonance Cone RF Probe, Rev. Sci. Instrum., 48, 485-487 (1977) 3 pages W. Gekelman, R. L. Stenzel, Particle and Wave Dynamics in a Magnetized Plasma Subject to High RF Pressure, Phys. Fluids 20,1316-1324 (1977) 9 pages R. L. Stenzel, W. Gekelman, Nonlinear Interactions of Focused Resonance Cone Fields with Plasmas, Phys. of Fluids, 20, 108-115 (1977) 8 pages W. Gekelman, R. L. Stenzel, Localized Fields and Density Perturbations Due to Self-Focusing of Nonlinear Lower-Hybrid Waves, Phys. Rev. Lett., 35, 1708-1710 (1975) 3 pages W. Gekelman, R. L. Stenzel, Large, Quiescent, Magnetized Plasma for Wave Studies, Rev. Sci. Instrum., 46, 1386-1393 (1975) 8 pages R. L. Stenzel, W. Gekelman, Electrostatic Waves Near the Lower Hybrid Frequency, Phys. Rev. A, 11, 2057-2060 (1975) 4 pages A.Y. Wong, J. M. Dawson, W. Gekelman, Z. Lucky, Production of Negative Ions and Generation of Intense Neutral Beams by Laser Irradiation, Applied Phys. Lett., 25, 579-580 (1974) 2 pages W. Gekelman, T. R. Hart, K.C. Rogers, R. O. Motz, Optical Measurement of the Ion Temperature in a Barium Q Plasma, Applied Phys. Lett., 21, 510-512 (1972) 3 pages
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Walter
Gekelman is a Fellow of the American Physical Society and professor
in the Department of Physics and Astronomy at UCLA where he has
been since 1974. He received a BS in physics from Brooklyn College
in 1966 and a Ph.D. in experimental plasma physics at Stevens Institute
of Technology in 1972. As a graduate student he built a Barium Q-machine
and developed optical systems for spectroscopic measurements related
to the current-driven (ion-cyclotron) instability. Before joining
UCLA he was a guest scientist at the Instituto Ellectrotechnico
Nazionale in Torino, Italy, where he constructed a "plasma focus"
device and used X-ray photography, X-ray scintillators, and neutron
detectors to study the plasma dynamics of the device. 
