Mark E. Koepke
Robert C. Byrd Professor of Physics
B.S., Physics/Astronomy (double major), University of Maryland, 1978
M. S., Physics, University of Maryland, 1980
Ph.D., Physics, University of Maryland, 1984
Office of Naval Research Young Investigator, title awarded in 1987
WVU Benedum Distinguished Scholar, title awarded in 2000
Distinguished Lecturer in Plasma Physics (American Physical Society’s Division of Plasma Physics), title awarded in 2001
Fellow of the American Physical Society, title awarded in 2004
Robert C. Byrd Professorship for outstanding achievements and leadership in research (WVU Research Corporation), title awarded in 2005
Deputy Editor, Plasma Physics and Controlled Fusion, 2005-present
Associate Editor, Journal of Plasma Physics, 2006- present
U.S. Member, International Union for Pure and Applied Physics, 2005-present
Fellow of the Japanese Society for the Promotion of Science, title awarded in 2005
Fellow of the Institute of Physics (United Kingdom), title awarded in 2006

Department of Physics
Hodges Hall, Room 138, Mail Stop 6315
West Virginia University
Morgantown, WV 26506-6315
Phone: (304) 293-3422 ext 1456
Fax: (304) 293-5732
Email: mkoepke@wvu.edu

Space consists predominantly of ionized gas, known as plasma. One of the outstanding issues in space plasma physics is the role of plasma waves and instabilities in the transport of mass, momentum, and energy in space plasmas. The large-scale plasma flow in space creates conditions that generate plasma waves at relatively small spatial and temporal scales. The spatial scales of the waves are typically from a few centimeters to a few hundreds of meters and the corresponding temporal scales are from a few microseconds to less than a second. On the other hand, large-scale plasma flows have scale lengths from a few thousands of kilometers to several Earth radii, and the temporal scales range from about an hour to days. Do the small-scale waves (microprocesses) significantly modify the large-scale flow? The answer is “probably,” and laboratory experiments performed on the WVU Q Machine are focused at answering such questions and confirming such hypotheses.

Our laboratory results are verifying important aspects of a recently predicted plasma instability used in theoretical models of space plasma processes. The characteristics of the instability differ in significant ways from all previous experimentally identified instabilities. By validating certain aspects of the existing theory, discovering new properties of the instability mechanism, and motivating and guiding the extension and revision of other aspects of the existing theory, our laboratory results contribute to a better understanding of the space processes, most of which cannot be subjected to controlled experimental investigation in the natural setting by virtue of the single-point nature of spacecraft measurements and the irreproducible behavior of the solar-terrestrial region of space. Several space plasma researchers have cited our work on velocity-shear-driven plasma instabilities in explaining the central role played by this new instability in the most common and intense ion heating in the auroral ionosphere.

A second thrust of my research is nonlinear dynamics, particularly in the area of driven oscillators. We have experimentally confirmed the theoretical model of a periodic nonlinear process known as periodic pulling, the measurable signatures of which have sometimes been mis-attributed to turbulent processes. We have demonstrated the spatio-temporal nature of this phenomenon in plasmas. Present investigations on driven nonlinear oscillators focus on spatio-temporal and nonstationary aspects of the periodic pulling process. These studies are being used to interpret mode transitions in plasma waves and may be applicable to mode transitions in hydrodynamics.

We are now preparing a large vacuum chamber for experiments on magnetized dusty plasma, to be a third thrust of my research. Plasma that contains, along with the usual electrons and positively charged ions, relatively massive, charged, solid dust grains with gyroradii much smaller than the plasma dimension perpendicular to the ambient magnetic field is termed “magnetized dusty plasma”.

Selected publications :

“A two-fluid model describing the finite conductivity, stationary Alfven
wave in anisotropic plasma,” S. M. Finnegan, M. E. Koepke, D. J. Knudsen,
Nonlin. Processes Geophys. 15, 957-964 (2008).

“Laboratory plasma physics,” M. E. Koepke, in Recent Research Developments
in Plasma Physics, 2007, J. Weiland, ed. (Transworld Research Network,
Kerala, India, 2008) chapter 7 (28 book pages, invited chapter).

“Interrelated laboratory and space plasma experiments,” M. E. Koepke,
Reviews of Geophysics 46, RG3001, doi:10.1029/2005RG000168, 16 July
(2008).

“The dispersive Alfvén wave in the time-stationary limit with a focus on
collisional and warm-plasma effects,” S. M. Finnegan, M. E. Koepke, and
D. J. Knudsen, Phys. Plasmas 15, 052108 (2008).

“Integrated campaign to study stationary Alfvén wave in the laboratory
and space regimes,” M. E. Koepke, S. M. Finnegan, S. Vincena, D. J.
Knudsen, C. Chaston, Plasma Physics and Controlled Fusion 50, 074004
(2008).

“Interrelationship between plasma phenomena in the laboratory and in
space,” M. E. Koepke, Plasma Physics and Controlled Fusion 50, 070201
(2008).

“Spectral characteristics of the collisional stationary Alfven wave in
the laboratory and space regimes,” S. M. Finnegan, M. E. Koepke, and D.
J. Knudsen, Plasma Physics and Controlled Fusion 50, 074005 (2008).

“Simulations of a plasmoid penetrating a magnetic barrier,” H. Gunell, T.
Hurtig, H. Nilsson, M. Koepke, and N. Brenning, Plasma Physics and
Controlled Fusion 50, 074013 (2008).

“Shear driven waves in the induced magnetosphere of Mars,” H. Gunell, U.
V. Amerstorfer, H. Nilsson, C, Grima, M. Koepke, M. Fränz, J. D.
Winningham, R. A. Frahm, J.-A. Sauvand, A. Fedorov, V. Erkaev, H. K.
Biernat, M. Holmström, R. Lundin, and S. Barabash, Plasma Physics and
Controlled Fusion 50, 074018 (2008).

“Simultaneous, co-located parallel-flow shear and perpendicular-flow shear in low-temperature, ionospheric-plasma relevant, laboratory plasma,” M. E. Koepke and E. W. Reynolds, Plasma Phys. Controlled Fusion 49, A145-A157 (May 2007).

“Investigation of a radio-frequency inductive-coupled-plasma discharge afterglow in noble gases,” C. A. DeJoseph, V. I. Demidov, J. C. Blessington, and M. E. Koepke, J. Phys. B: Atomic, Molecular, and Optical Physics, 40, 3823-3833 (October 2007).

“Dynamics of small dust clouds trapped in a magnetized anodic plasma,” I. Pilch, A. Piel, T. Trottenberg, and M. E. Koepke, Phys. Plasmas, 12, 123704 (December 2007, 8 pages).

“Laboratory plasma physics,” M. E. Koepke, in Recent Research Developments
in Plasma Physics, 2007, J. Weiland, ed. (Transworld Research Network,
Kerala, India, 2008) chapter 7 (28 book pages, invited chapter).

“Baffled-probe cluster for simultaneous, single-point monitoring of
magnetized plasma fluctuations,” M. E. Koepke, V. I. Demidov, S. M.
Finnegan, and E. W. Reynolds, Contrib. Plasma Phys. 46, 395-401 (2006).

“Inhomogeneity scale lengths in a magnetized, low temperature,
collisionless, Q-machine plasma column containing perpendicular-velocity
shear,” E. W. Reynolds, M. E. Koepke, J. J. Carroll, and S. Shinohara,
Phys. Plasmas 13, 092106 (2006). 12 pages

“Electron parallel-flow shear driven low-frequency electromagnetic modes
in collisionless magnetoplasma,” P. K. Shukla, B. Eliasson, and M.
Koepke, Phys. Plasmas 13, 052115 (2006). 6 pages

“Radiation from an electron beam in a magnetized plasma: Whistler mode
wave packets,” N. Brenning, I. Axnäs, M. A. Raadu, E. Tennfors, and M.
Koepke, J. Geophys. Res. 111, A

“Simultaneous, co-located parallel-flow shear and perpendicular-flow shear in low-temperature, ionospheric-plasma relevant, laboratory plasma,” M. E. Koepke and E. W. Reynolds, Plasma Phys. Controlled Fusion 49, A145-A157 (May 2007).

“Investigation of a radio-frequency inductive-coupled-plasma discharge afterglow in noble gases,” C. A. DeJoseph, V. I. Demidov, J. C. Blessington, and M. E. Koepke, J. Phys. B: Atomic, Molecular, and Optical Physics (J. Phys. B: At. Mol. Opt. Phys.), 40, 3823-3833 (2007).

“Baffled-probe cluster for simultaneous, single-point monitoring of magnetized plasma fluctuations,” M. E. Koepke, V. I. Demidov, S. M. Finnegan, and E. W. Reynolds, Contrib. Plasma Phys. 46, 395-401 (2006).

Inhomogeneity scale lengths in a magnetized, low temperature, collisionless, Q-machine plasma column containing perpendicular-velocity shear,” E. W. Reynolds, M. E. Koepke, J. J. Carroll, and S. Shinohara, Phys. Plasmas 13, 092106 (2006). 12 pages

“Radiation from an electron beam in a magnetized plasma: Whistler mode wave packets,” N. Brenning, I. Axnäs, M. A. Raadu, E. Tennfors, and M. Koepke, J. Geophys. Res. 111, A11212, doi:10.1029/2006JA011739 (2006).

“Electron parallel-flow shear driven low-frequency electromagnetic modes in collisionless magnetoplasma,” P. K. Shukla, B. Eliasson, and M.Koepke, Phys. Plasmas 13, 052115 (2006). 6 pages

“Inhomogeneity scale lengths in a magnetized, low temperature, collisionless, Q-machine plasma column containing perpendicular-velocity shear,” E. W. Reynolds, M. E. Koepke, J. J. Carroll, and S. Shinohara, Phys. Plasmas 13, 092106 (2006). 12 pages

“Electron parallel-flow shear driven low-frequency electromagnetic modes in collisionless magnetoplasma,” P. K. Shukla, B. Eliasson, and M. Koepke, Phys. Plasmas 13, 052115 (2006). 6 pages

“Radiation from an electron beam in a magnetized plasma: Whistler mode wave packets,” N. Brenning, I. Axnäs, M. A. Raadu, E. Tennfors, and M.Koepke, J. Geophys. Res. 111, A11212, doi:10.1029/2006JA011739 (2006).

“Velocity-shear-driven drift waves with simultaneous modes in a barium-ion Q-machine plasma,” T. Kaneko, E. Reynolds, R. Hatakeyama, and M. Koepke, Phys. Plasmas, 12, 102106 (2005).

Laser-induced-fluorescence characterization of velocity shear in a magnetized plasma column produced by a segmented Q-machine source, E. W. Reynolds, T. Kaneko, M. E. Koepke, and R. Hatakeyama, Phys. Plasmas, 12, 072103 (2005).

On interrelating laboratory experiments and geoplasma observations, M. E. Koepke, Plasma Phys. Contr. Fusion, 47, B727-B734 (2005).

Effect of the bounce orbit’s turning-point location on bounce-resonance Landau damping, M. E. Koepke, Physica Scripta, T116, 107 (2005). (online article number: t116p01a00107)

Lower-hybrid cavity density depletions as a result of transverse ion acceleration localized on the gyroradius scale, D. Knudsen, B. J. J. Block, S. R. Bounds, J. K. Burchill, J. H. Clemmons, J. D. Curtis, A. I. Eriksson, M. E. Koepke, R. F. Pfaff, D. D. Wallis, and N. Whaley, J. Geophys. Res., 109, A04212, doi:10.1029/2003JA010089 (20 April 2004).

Sheared-flow-driven electrostatic waves in laboratory and space plasmas, M. E. Koepke, Physica Scripta, T107, 182-187 (2004).

Utility of a baffled probe for applications to edge plasma and turbulence characterization in stellarator plasma, W. Guttenfelder, C. Lechte, M. E. Koepke, and V. I. Demidov, Rev. Sci. Instrum., 75, 3622 (2004).

Utility of a baffled probe for measurements of oscillations in magnetized plasma, V. I. Demidov, S. M. Finnegan, M. E. Koepke, and E. W. Reynolds, Contrib. Plasma Physics, 44, 689-694 (2004).

On the role of ion-temperature anisotropy in the growth and propagation of ion-acoustic waves, C. Teodorescu, M. E. Koepke, and E. W. Reynolds, J. Geophys. Res., 108, SMP 25.1 – 25.9 (2003).

Baffled probe for real-time measurement of space potential in magnetized plasma, V. I. Demidov, S. M. Finnegan, M. E. Koepke, and E. W. Reynolds, Rev. Sci. Instrum., 74, 4558 (2003).

Laboratory-device configurations for investigating new dusty-plasma equilibria, M. E. Koepke and N. Sato, New Journal of Physics, 5, 42.1 – 42.14 (2003) http://www.njp.org.

Space-relevant laboratory studies of ion-acoustic and ion-cyclotron waves driven by parallel-velocity shear, M. E. Koepke, C. Teodorescu, and E. W. Reynolds, Plasma Phys. Contr. Fusion, 45, 869-889 (2003).

Resonant-to-nonresonant transition in electrostatic ion-cyclotron phase velocity, J. J. Carroll III, M. E. Koepke, M. W. Zintl, and V. Gavrishchaka, Nonlinear Processes in Geophysics, 10, 131-138 (2003).

Inverse ion-cyclotron damping: Laboratory documentation and space ramifications, M. E. Koepke, C. Teodorescu, E. R. Reynolds, C. C. Chaston, C. W. Carlson, J. P. McFadden, and R. E. Ergun, Phys. Plasmas, 10, 1605-1613 (2003).

On the role of ion-temperature anisotropy in the growth and propagation of shear-modified ion-acoustic waves, C. Teodorescu, M. E. Koepke, and E. W. Reynolds, J. Geophys. Res., 108, SMP-25 (2003).

Evidence for thermal anisotropy effects on shear modified ion-acoustic instabilities, E. E. Scime, A. M. Keesee, R. S. Spangler, M. E. Koepke, C. Teodorescu, and E. W. Reynolds, Phys. Plasmas, 9, 4399 (2002).

Observation of inverse ion-cyclotron damping induced by parallel-velocity shear, C. Teodorescu, E. W. Reynolds, and M. E. Koepke, Phys. Rev. Lett., 89, 105001 (2002).

Inhomogeneous magnetic-field-aligned ion flow measured in a Q machine, M. E. Koepke, M. W. Zintl, C. Teodorescu, E. W. Reynolds, G. Wang, and T. N. Good, Phys. Plasmas, 9, 3225 (2002).

Experimental verification of the shear-modified ion-acoustic instability, C. Teodorescu, E. W. Reynolds, and M. E. Koepke, Phys. Rev. Lett., 88, 185003 (2002).

Contributions of Q-machine experiments to understanding auroral particle acceleration processes, M. E. Koepke, Phys. Plasmas, 9, 2420 (2002).

Spatio-temporal signatures of periodic pulling during ionization-wave mode transitions, M. E. Koepke, A. Dinklage, T. Klinger, and C. Wilke, Phys. Plasmas, 8, 1432 (2001).

Inhomogeneous transverse electric fields and wave generation in the auroral region: A statistical study, M. Hamrin, M. André, G. Ganguli, V. V. Gavrishchaka, M. E. Koepke, M. W. Zintl, N. Ivchenko, T. Karlsson, and J. H. Clemmons, J. Geophys. Res., 106, 10803 (2001).

Spatio-temporal laser perturbation of competing ionization waves in a neon glow discharge, K.-D. Weltmann, M. E. Koepke, and C. A. Selcher, Phys. Rev. E., 62, 2773 (2000).

Laboratory simulation of broadband ELF waves in the auroral ionosphere, M. E. Koepke, J. J. Carroll III, and M. W. Zintl, J. Geophys. Res., 104, 14397 (1999).

Broadband electric-field spectral power density associated with electrostatic ion-cyclotron waves, M. E. Koepke, M. W. Zintl, and J. J. Carroll III, in Physics of Space Plasmas (1998), T. Chang and J. R. Jasperse, eds. (MIT Center for Theoretical Geo/Cosmo Plasma Physics, Cambridge, MA, 1998) p. 221.

Excitation and propagation of electrostatic ion-cyclotron waves in plasma with structured transverse flow, M. E. Koepke, J. J. Carroll III, and M. W. Zintl, Phys. Plasmas, 5, 1671 (1998).

An effect of neutral collisions on the excitation threshold of electrostatic ion-cyclotron waves, M. E. Koepke, M. W. Zintl, and T. N. Good, Geophys. Res. Lett., 25, 3095 (1998).

Velocity-shear origin of low-frequency electrostatic ion-gyroresonant waves, J.J. Carroll III, M. E. Koepke, M. W. Zintl, and V. Gavrishchaka, Geophys. Res. Lett., 25, 3099 (1998).

Control of ion temperature anisotropy in a helicon plasma, E. Scime, P. Keiter, M. Zintl, M. Balkey, J. Kline, and M. Koepke, Plasma Sources Sci. Technol., 7, 186 (1998).

Velocity-shear-driven ion-cyclotron waves and associated transverse ion heating, W. E. Amatucci, D. N. Walker, G. Ganguli, D. Duncan, J. A. Antoniades, J. H. Bowles, V. Gavrishchaka, and M. E. Koepke, J. Geophys. Res., 103, 11711 (1998).

Simultaneous observation of multiple nonlocal eigenmodes of an inhomogeneity-driven plasma instability, M. E. Koepke, J. J. Carroll III, M. W. Zintl, C. A. Selcher, and V. Gavrishchaka, Phys. Rev. Lett., 80, 1441 (1998).

High-order nonlocal formalism for linear analysis of a magnetized multi-species plasma with inhomogeneous flows, V. V. Gavrishchaka, G. I. Ganguli, P. M. Bakshi, and M. E. Koepke, Phys. Plasmas, 5, 10 (1998).

A simple Langmuir probe for alkali plasmas, D. Strele, M. Koepke, R. Schrittwieser, and P. Winkler, Rev. Sci. Instrum., 67, 3751 (1997).

Perpendicular ion heating by velocity-shear-driven waves, D. N. Walker, W. E. Amatucci, G. Ganguli, J. A. Antoniades, J. H. Bowles, D. Duncan, V. Gavrishchaka, and M. E. Koepke, Geophys. Res. Lett., 24, 1187 (1997).

Observation of velocity-shear-driven instabilities in a sodium plasma (invited), J. J. Carroll III, M. E. Koepke, M. W. Zintl, C. A. Selcher, V. Gavrishchaka, and E. Csomortani in Double Layers – Potential Formation and Related Nonlinear Phenomena in Plasmas (World Scientific, Singapore, 1997) p. 283

Space Chamber Investigations of Transverse Velocity Shear Driven Plasma Waves, W. E. Amatucci, D. N. Walker, G. Ganguli, J. A. Antoniades, D. Duncan, J. Bowles, V. Gavrishchaka, and M. E. Koepke in Double Layers – Potential Formation and Related Nonlinear Phenomena in Plasmas (World Scientific, Singapore, 1997) p. 277

Ion-cyclotron modes in a two-ion-component plasma with transverse-velocity shear, V. V. Gavrishchaka, M. E. Koepke, and G. Ganguli, J. Geophys. Res., 102, 11653 (1997).

Periodic nonlinear wave-wave interaction in a plasma discharge with no external oscillatory force, M. E. Koepke, T. Klinger, F. Seddighi, and A. Piel, Phys. Plasmas, 3, 4421 (1996).

Plasma response to strongly sheared flow, W. E. Amatucci, D. N. Walker, J. A. Antoniades, G. Ganguli, D. Duncan, J. H. Bowles, V. Gavrishchaka, and M. E. Koepke, Phys. Rev. Lett., 77, 1978 (1996).

Dispersive properties of a magnetized plasma with a field-aligned drift and inhomogeneous transverse flow, V. Gavrishchaka, M. E. Koepke, and G. Ganguli, Phys. Plasmas, 3, 3091 (1996).

Inhomogeneity scale lengths in the WVU Q machine, J. J. Carroll and M. E. Koepke, in Physics of Space Plasmas (1995), T. Chang and J. R. Jasperse, eds. (MIT Center for Theoretical Geo/Cosmo Plasma Physics, Cambridge, MA, 1996) p. 625-632.

Frequency range and spectral width of waves associated with transverse-velocity shear, V. Gavrishchaka, M. E. Koepke, J. J. Carroll III, W. E. Amatucci, and G. Ganguli, in Cross-Scale Coupling in Space Plasma, Geophysical Monograph Series, vol. 93, Horwitz, Singh, and Burch, eds. (AGU, Washington, D.C., 1995) p. 81-85.

van der Pol behavior of relaxation oscillations in a periodically driven thermionic discharge, T. Klinger, F. Greiner, A. Rohde, A. Piel, and M. Koepke, Phys Rev. E, 52, 4316 (1995).

Velocity-shear-induced ion-cyclotron turbulence: Laboratory identification and space applications, M. E. Koepke, W. E. Amatucci, J. J. Carroll III, V. Gavrishchaka, and G. Ganguli, Phys. Plasmas, 2, 2523 (1995).

A segmented disk electrode to produce and control parallel and transverse particle drifts in a cylindrical plasma, J. J. Carroll III, M. E. Koepke, W. E. Amatucci, T. E. Sheridan, and M. J. Alport, Rev. Sci. Instrum., 65, 2991 (1994).

Observation of ion-cyclotron turbulence at small values of magnetic field-aligned current, W. E. Amatucci, M. E. Koepke, J. J. Carroll III, and T. E. Sheridan, Geophys. Res. Lett., 21, 1595 (1994).

Experimental verification of the inhomogeneous energy-density driven instability, M. E. Koepke, W. E. Amatucci, J. Carroll, and T. E. Sheridan, Phys. Rev. Lett., 72, 3355 (1994).

Asymmetric spectral broadening of modulated electrostatic ion-cyclotron waves, M. E. Koepke, M. J. Alport, T. E. Sheridan, W. E. Amatucci, and J. J. Carroll III, Geophys. Res. Lett., 21, 1011 (1994).

Observation of small-integer dimensionality in a system with complicated spectra, M. E. Koepke, T. E. Sheridan, and M. R. Millecchia, in Physics of Space Plasmas (1993), T. Chang and J. R. Jasperse, eds. (MIT Center for Theoretical Geo/Cosmo Plasma Physics, Cambridge, MA, 1994) p. 178.

Periodic pulling in a driven relaxation oscillator, T. E. Sheridan, M. E. Koepke, C. A. Selcher, and T. N. Good, in Proc. of SPIE, 2039, 158 (1993).

Effects of a transverse, localized, electric field on the electrostatic ion-cyclotron instability, M. E. Koepke, W. E. Amatucci, J. J. Carroll III, M. J. Alport, and T. E. Sheridan, in Auroral Plasma Dynamics, AGU Monograph #80, R. Lysak, ed. (American Geophysical Union, Washington, D.C., 1993) p. 287.

Self-cleaning Langmuir probe, W. E. Amatucci, M. E. Koepke, T. E. Sheridan, M. J. Alport, and J. J. Carroll III, Rev. Sci. Instrum., 64, 1352-1356 (1993).

Effects of periodic pulling on spontaneous oscillations, M. E. Koepke, T. E. Sheridan, and M. J. Alport, in Physics of Space Plasmas (1992), T. Chang and J. R. Jasperse, eds. (Scientific Publishers, Cambridge, MA, 1992) p. 551.

Electrostatic ion-cyclotron experiments in the WVU Q machine, M. E. Koepke and W. E. Amatucci, IEEE Trans. Plasma Sci., PS-20, 631 (1992).

Effect of bounce resonance damping on the harmonics of a plasma microinstability, M. E. Koepke, Phys. Fluids B, 4, 1193 (1992).

Experimental verification of periodic pulling in a nonlinear electronic oscillator, M. E. Koepke and D. M. Hartley, Phys. Rev. A, 44, 6877 (1991).

Experimental studies of linear high-beta heliac plasma configurations, C. M. Greenfield, M. E. Koepke and F. L. Ribe, Phys. Fluids B, 2, 133 (1990)

Theoretical modeling of DCLC radial mode structure measurements, G. R. Burkhart, P. N. Guzdar, and M. E. Koepke, Phys. Fluids B, 1, 570 (1989).

Experimental studies of the equilibrium of a linear high beta ÿ=1 stellarator, E. R. Hedin, M. E. Koepke, and F. L. Ribe, Phys. Fluids, 30, 2885 (1987)

Experimental studies of the dynamics of a linear high-beta stellerator, E. R. Hedin, M. E. Koepke, and F. L. Ribe, Phys. Fluids, 30, 3821 (1987)

Optimizing hot-ion production from a gas-injected washer gun, M. J. McCarrick, R. F. Ellis, J. H. Booske, and M. Koepke, J. Appl. Phys., 61, 1747 (1987).

Experimental observation of bounce-resonance Landau damping in an axisymmetric mirror plasma, M. Koepke, R. F. Ellis, R. P. Majeski, and M. J. McCarick, Phys. Rev. Lett., 56, 1256 (1986)

Three-dimensional mode structure of the drift cyclotron loss-cone instability in a mirror trap, M. Koepke, M. J. McCarrick, R. P. Majeski, and R. F. Ellis, Phys. Fluids, 29, 3439 (1986)

Perpendicular ion energy analyzer for hot ion plasmas, M. J. McCarrick, R. F. Ellis, M. Koepke, and R. P. Majeski, Rev. Sci. Instrum., 56, 1463 (1985)

Interaction of lower-hybrid waves with the current-driven ion acoustic instability, R. P. Majeski, M. Koepke, and R. F. Ellis, Plasma Phys. Contr. Fusion, 26, 373 (1984).

A preshaping transition coil for a small min-B mirror, M. Koepke, R. P. Majeski, and R. F. Ellis, IEEE Trans. Plasma Sci., PS-11, 299 (1983).
“Simultaneous, co-located parallel-flow shear and perpendicular-flow shear in low-temperature, ionospheric-relevant laboratory plasma,” M. E. Koepke and E. W. Reynolds, Plasma Phys. Control. Nuclear Fusion (to appear May 2007).

“Baffled-probe cluster for simultaneous, single-point monitoring of magnetized plasma fluctuations,” M. E. Koepke, V. Demidov, S. Finnegan, and E. W. Reynolds, Contrib. Plasma Phys. 46, 385-391 (2006).

“Inhomogeneity scale lengths in a magnetized, low temperature, collisionless, Q-machine plasma column containing perpendicular-velocity shear,” E. W. Reynolds, M. E. Koepke, J. J. Carroll, and S. Shinohara, Phys. Plasmas 13, 092106 (2006).

“Electron parallel-flow shear driven low-frequency electromagnetic modes in collisionless magnetoplasma,” P. K. Shukla, B. Eliasson, and M. E. Koepke, Phys. Plasmas 13, 052115 (2006).

“Radiation from an electron beam in a magnetized plasma: Whistler mode wave packets,” N. Brenning, I. Axnas, M. Raadu, E. Tennfors, and M. Koepke, J. Geophys. Res. 111, A11212, doi:10.1029/2006JA011739 (2006).

“Laser-induced-fluorescence characterization of velocity shear in a magnetized plasma column produced by a segmented, Q-machine source,” E. W. Reynolds, T. Kaneko, M. E. Koepke, and R. Hatakeyama, Phys. Plasmas 12, 072103 (2005).

“Velocity-shear-driven drift waves with simultaneous modes in a barium-ion Q-machine plasma,” T. Kaneko, E. W. Reynolds, R. Hatakeyama, and M. E. Koepke, Phys. Plasmas 12, 102106 (2005).

“Effect of the bounce orbit?s turning-point locataion on bounce-resonance Landau damping,” M. E. Koepke, Physica Scripta T116, 107 (2005).

“On interrelating laboratory experiments and geoplasma observations,” M. E. Koepke, Plasma Phys. Controlled Fusion 47, B727-B734 (2005).

“Utility of a baffled probe for measurements of oscillations in magnetized plasma,” V. I. Demidov, S. M. Finnegan, M. E. Koepke, and E. W. Reynolds, Contrib. Plasma Physics 44, 689-694 (2004)

“Lower-hybrid cavity density depletions as a result of transverse ion acceleration localized on the gyroradius scale,” D. J. Knudsen, B. J. J. Bock, S. R. Bounds, J. K. Burchill, J. H. Clemmons, J. D. Curtis, A. I. Eriksson, M. E. Koepke, R. F. Pfaff, D. D. Wallis, and N. Whaley, J. Geophys. Res., 109, A04212, doi:10.1029/2003JA010089 (20 April 2004).

“Sheared-flow-driven electrostatic waves in laboratory and space plasma,” M. E. Koepke, Physica Scripta T107, 182-187 (2004).

“Utility of a baffled Langmuir probe for applications to edge plasma and turbulence characterization in stellarator plasma,” W. Guttenfelder, C. Lechte, M. E. Koepke, and V. I. Demidov, Rev. Sci. Instrum. 75, 3622 (2004).

“On the role of ion-temperature anisotropy in the growth and propagation of ion-acoustic waves,” C. Teodorescu, M. E. Koepke, E. W. Reynolds, J. Geophys. Res. 108, SMP 25.1 – 25.10 (2003).

“Resonant-to-nonresonant transition in electrostatic ion-cyclotron phase velocity,” J. J. Carroll III, M. E. Koepke, M. W. Zintl, and V. Gavrishchaka, Nonlinear Processes in Geophysics 10, 131-138 (2003).

“Space-relevant studies of ion-acoustic and ion-cyclotron,” M. E. Koepke, C. Teodorescu, and E. W. Reynolds, Plasma Phys. and Controlled Fusion 45, 869-889 (2003).

“Laboratory-device configurations for investigating new dusty-plasma equilibria,” M. E. Koepke and N. Sato, New Journal of Physics 5, 42.1-42.14 (2003).

“Inverse ion-cyclotron damping: Laboratory demonstration and space ramifications,” M. E. Koepke, C. Teodorescu, E. W. Reynolds, C. C. Chaston, C. W. Carlson, J. P. McFadden, and R. E. Ergun, Phys. Plasmas 10, 1605-1613 (2003).

“A baffeled probe for real-time measurements of space potential in magnetized plasma,” V. I. Demidov, S. M. Finnegan, M. E. Koepke, and E. W. Reynolds, Rev. Sci. Instrum. 74 , 4558 (2003).

“Contributions of Q-machine experiments to understanding auroral particle acceleration,” M. E. Koepke, Phys. Plasmas, 9, 2420-2427 (2002).

“Experimental verification of the shear-modified ion-acoustic instability,” C. Teodorescu, E. W. Reynolds, and M. E. Koepke, Phys. Rev. Lett., 88, 185003 (2002).

“Inhomogeneous magnetic-field-aligned ion flow measured in a Q machine,” M. E. Koepke, M. W. Zintl, C. Teodorescu, E. W. Reynolds, G. Wang, and T. N. Good, Phys. Plasmas, 9, 3225-3235 (2002).

“Observation of inverse ion-cyclotron damping induced by parallel-velocity shear,” C. Teodorescu, E. W. Reynolds, and M. E. Koepke, Phys. Rev. Lett., 89, 105001 (2002).

“Evidence for thermal anisotropy effects on shear modified ion acoustic instabilities,” E. E. Scime, A. M. Keesee, R. S. Spangler, M. E. Koepke, C. Teodorescu, and E. W. Reynolds, Phys. Plasmas 9, 4399-4401 (2002).

“Counter-streaming ion beams with inhomogeneous density profiles,” M. E. Koepke, M. W. Zintl, E. M. Johnson, and E. W. Reynolds, and T. N. Good, Proceedings of the 2000 International Conference on Plasma Physics, Quebec City, Canada (European Physical Society, Geneva, 2001) p. 45.

“Spatio-temporal signatures of periodic pulling during ionization-wave mode transitions,” M. E. Koepke, A. Dinklage, T. Klinger, and C. Wilke, Phys. Plasmas 8, 1432-1436 (2001).

“Inhomogeneous transverse electric fields and wave generation in the auroral region: A statistical study,” M. Hamrin, M. AndrÃ??Ã?©, G. Ganguli, V. V. Gavrishchaka, M. E. Koepke, M. W. Zintl, N. Ivchenko, T. Karlsson, and J. H. Clemmons, J. Geophys. Res., 106, 10803-10816 (2001).

“Spatio-temporal laser perturbation of competing ionization waves in a neon glow discharge,” K.-D. Weltmann, M. E. Koepke, and C. A. Selcher, Phys. Rev. E. 62, 2773-2781 (2000).

“Laboratory simulation of broadband ELF waves in the auroral ionosphere,” M. E. Koepke, J. J. Carroll III, and M. W. Zintl, J. Geophys. Res. 104, 14397-14415 (1999).

“Excitation and propagation of electrostatic ion-cyclotron waves in plasma with structured transverse flow,” M. E. Koepke, J. J. Carroll III, and M. W. Zintl, Phys. Plasmas 5, 1671-1680 (1998).

“An effect of neutral collisions on the excitation threshold of electrostatic ion-cyclotron waves,” M. E. Koepke, M. W. Zintl, and T. N. Good, Geophys. Res. Lett. 25, 3095-3098 (1998).

“Velocity-shear origin of low-frequency electrostatic ion-gyroresonant waves,” J.J. Carroll III, M. E. Koepke, M. W. Zintl, and V. Gavrishchaka, Geophys. Res. Lett. 25, 3099-3102 (1998).

“Control of ion temperature anisotropy in a helicon plasma,” E. Scime, P. Keiter, M. Zintl, M. Balkey, J. Kline, and M. Koepke, Plasma Sources Sci. Technol. 7, 186-191 (1998).

“Velocity-shear-driven ion-cyclotron waves and associated transverse ion heating,” W. E. Amatucci, D. N. Walker, G. Ganguli, D. Duncan, J. A. Antoniades, J. H. Bowles, V. Gavrishchaka, and M. E. Koepke, J. Geophys. Res., 103, 11711-11724 (1998).

“Simultaneous observation of multiple nonlocal eigenmodes of an inhomogeneity driven plasma instability,” M. E. Koepke, J. J. Carroll III, M. W. Zintl, C. A. Selcher, and V. Gavrishchaka, Phys. Rev. Lett., 80, 1441-1444 (1998).

“High-order nonlocal formalism for linear analysis of a magnetized multi-species plasma with inhomogeneous flows,” V. V. Gavrishchaka, G. I. Ganguli, P. M. Bakshi, and M. E. Koepke, Phys. Plasmas, 5, 10-21 (1998).

“Broadband electric-field spectral power density associated with electrostatic ion-cyclotron waves,” M. E. Koepke, M. W. Zintl, and J. J. Carroll III, in Physics of Space Plasmas (1998), T. Chang and J. R. Jasperse, eds. (MIT Center for Theoretical Geo/Cosmo Plasma Physics, Cambridge, MA, 1998) p. 221-226.

“A simple Langmuir probe for alkali plasmas,” D. Strele, M. Koepke, R. Schrittwieser, and P. Winkler, Rev. Sci. Instrum., 67, 3751-3754 (1997).

“Perpendicular ion heating by velocity-shear-driven waves,” D. N. Walker, W. E. Amatucci, G. Ganguli, J. A. Antoniades, J. H. Bowles, D. Duncan, V. Gavrishchaka, and M. E. Koepke, Geophys. Res. Lett., 24, 1187-1190 (1997).

“Ion-cyclotron modes in a two-ion-component plasma with transverse-velocity shear,” V. V. Gavrishchaka, M. E. Koepke, and G. Ganguli, J. Geophys. Res., 102, 11653-11663 (1997).

“Periodic nonlinear wave-wave interaction in a plasma discharge with no external oscillatory force,” M. E. Koepke, T. Klinger, F. Seddighi, and A. Piel, Phys. Plasmas, 3, 4421-4426 (1996).

“Plasma response to strongly sheared flow,” W. E. Amatucci, D. N. Walker, J. A. Antoniades, G. Ganguli, D. Duncan, J. H. Bowles, V. Gavrishchaka, and M. E. Koepke, Phys. Rev. Lett., 77, 1978-1981 (1996).

“Dispersive properties of a magnetized plasma with a field-aligned drift and inhomogeneous transverse flow,” V. Gavrishchaka, M. E. Koepke, and G. Ganguli, Phys. Plasmas, 3, 3091-3106 (1996).

“van der Pol behavior of relaxation oscillations in a periodically driven thermionic discharge,” T. Klinger, F. Greiner, A. Rohde, A. Piel, and M. Koepke, Phys Rev. E, 52, 4316-4327 (1995).

“Velocity-shear-induced ion-cyclotron turbulence: Laboratory identification and space applications,” M. E. Koepke, W. E. Amatucci, J. J. Carroll III, V. Gavrishchaka, and G. Ganguli, Phys. Plasmas, 2, 2523-2531 (1995).

“A segmented disk electrode to produce and control parallel and transverse particle drifts in a cylindrical plasma,” J. J. Carroll III, M. E. Koepke, W. E. Amatucci, T. E. Sheridan, and M. J. Alport, Rev. Sci. Instrum., 65, 2991-2995 (1994).

“Observation of ion-cyclotron turbulence at small values of magnetic field-aligned current,” W. E. Amatucci, M. E. Koepke, J. J. Carroll III, and T. E. Sheridan, Geophys. Res. Lett., 21, 1595-1598 (1994).

“Experimental verification of the inhomogeneous energy-density driven instability,” M. E. Koepke, W. E. Amatucci, J. Carroll, and T. E. Sheridan, Phys. Rev. Lett., 72, 3355-3358 (1994).

“Asymmetric spectral broadening of modulated electrostatic ion-cyclotron waves,” M. E. Koepke, M. J. Alport, T. E. Sheridan, W. E. Amatucci, and J. J. Carroll III, Geophys. Res. Lett., 21, 1011-1014 (1994).

“Periodic pulling in a driven relaxation oscillator,” T. E. Sheridan, M. E. Koepke, C. A. Selcher, and T. N. Good, in Proc. of SPIE, 2039, 158-167 (1993).

“Self-cleaning Langmuir probe,” W. E. Amatucci, M. E. Koepke, T. E. Sheridan, M. J. Alport, and J. J. Carroll III, Rev. Sci. Instrum., 64, 1352-1356 (1993).

“Electrostatic ion-cyclotron experiments in the WVU Q machine,” M. E. Koepke and W. E. Amatucci, IEEE Trans. Plasma Sci., PS-20, 631-635 (1992).

“Effect of bounce resonance damping on the harmonics of a plasma microinstability,” M. E. Koepke, Phys. Fluids B 4, 1193-1198 (1992).

“Experimental verification of periodic pulling in a nonlinear electronic oscillator,” M. E. Koepke and D. M. Hartley, Phys. Rev. A, 44, 6877-6887 (1991).

“Experimental studies of linear high-beta heliac plasma configurations,” C. M. Greenfield, M. E. Koepke and F. L. Ribe, Phys. Fluids B 2, 133-142 (1990).

“Theoretical modeling of DCLC radial mode structure measurements,” G. R. Burkhart, P. N. Guzdar, and M. E. Koepke, Phys. Fluids B 1, 570-580 (1989).

“Experimental studies of the equilibrium of a linear high beta l=1 stellarator,” E. R. Hedin, M. E. Koepke, and F. L. Ribe, Phys. Fluids, 30, 2885-3892 (1987).

“Experimental studies of the dynamics of a linear high-beta stellerator,” E. R. Hedin, M. E. Koepke, and F. L. Ribe, Phys. Fluids, 30, 3821-3824 (1987).

“Optimizing hot-ion production from a gas-injected washer gun,” M. J. McCarrick, R. F. Ellis, J. H. Booske, and M. Koepke, J. Appl. Phys., 61, 1747-1752 (1987).

“Experimental observation of bounce-resonance Landau damping in an axisymmetric Mirror Plasma,” M. Koepke, R. F. Ellis, R. P. Majeski, and M. J. McCarick, Phys. Rev. Lett., 56, 1256-1259 (1986).

“Three-dimensional mode structure of the drift cyclotron loss-cone instability in a mirror trap,” M. Koepke, M. J. McCarrick, R. P. Majeski, and R. F. Ellis, Phys. Fluids, 29, 3439-3444 (1986).

“Perpendicular ion energy analyzer for hot ion plasmas,” M. J. McCarrick, R. F. Ellis, M. Koepke, and R. P. Majeski, Rev. Sci. Instrum., 56, 1463-1464 (1985).

“Interaction of lower-hybrid waves with the current-driven ion acoustic instability,” R. P. Majeski, M. Koepke, and R. F. Ellis, Plasma Phys. Contr. Fusion, 26, 373-385 (1984).

“A preshaping transition coil for a small min-B mirror,” M. Koepke, R. P. Majeski, and R. F. Ellis, IEEE Trans. Plasma Sci., PS-11, 299-300 (1983).