Student Bios

 

Teresa Bartal, M.S.
University of California, San Diego
Lawrence Livermore National Laboratoryy
Advisor: Farhat Beg
Pursuing Ph.D. in Mechanical Engineering (Plasma Physics)

Teresa's research focuses on the physics of the production and characteristics of a proton beam relevant to Fast Ignition (FI).  Proton FI is an alternative to electron FI within the Inertial Confinement Fusion scheme.  Starting with the concept of cone-guided FI, in proton FI a hemispherical segment is placed within the conical structure, which will produce and focus a proton beam, originating from contaminants on the rear side of the segment, when it is irradiated by an ultra-high-intensity short pulse laser.  There are two key issues for proton FI: laser to proton conversion efficiency and the characteristics of proton focusing.  Teresa has participated in experiments conducted on the Trident laser at LANL, the Titan laser at LLNL and on OMEGA EP at LLE.

Publications:

  1. Observations or proton beam enhancement due to erbium hydride on gold foil targets D. T. Offermann, R .R. Freeman, L. D. Van Woerkom, M. E. Foord, D. Hey, M. H. Key, A. J. Mackinnon, A. G. MacPhee, P. K. Patel, Y. Ping, J. J. Sanchez, N. Shen, T. Bartal , F. N. Bartal, L. Espada, and C. D. Chen, Phys. Plasmas 16 , 093113 (2009)
  2. Laser-Accelerated Proton Conversion Efficiency Thickness Scaling D. S. Hey, M. E. Foord, M. H. Key, S. L. LePape, A. J. Mackinnon, P. K. Patel, Y. Ping, K. U. Akli, R. B. Stephens, T. Bartal , F. N. Beg, R. Fedosejevs, H. Friesen, H. F. Tiedje, Y. Y. Tsue, submitted to Phys. Plasmas .
  3. Absolute calibration of image plates for electrons at energy between 100 keV and 4 MeV H. Chen, N. L. Back, T. Bartal , F. N. Beg, D. C. Eder, A. Link, A. G. MacPhee, Y. Ping, P. M. Song, A. Throop, and L. Van Woerkom, Rev. Sci. Instruments 79 , 033301 (2008)
  4. Fast Electron Generation in Cones with Ultraintense Laser Pulses L. Van Woerkom, K. U. Akli, T. Bartal , F. N. Beg, S. Chawla, C. D. Chen, E. Chowdhury, R. R. Freeman, D. Hey, M. H. Key, J. A. King, A. Link, T. Ma , A. J. MacKinnon, A. G. MacPhee, D. Offermann, V. Ovchinnikov, P. K. Patel, D. W. Schumacher, R. B. Stephens, and Y. Y. Tsui, Phys. of Plasmas 15 , 056304 (2008)
  5. Bremsstrahlung and K a fluorescence measurements for inferring conversion efficiencies into fast ignition relevant hot electrons C. D. Chen, P. K. Patel, D. S. Hey, A. J. Mackinnon, M. H. Key, K. U. Akli, T. Bartal , F. N. Beg, S. Chawla, H. Chen, R. R. Freeman, D. P. Higginson, A. Link, T. Ma, A. G. MacPhee, R. B. stephens, L. d. Van woerkom, B. Westover, and M. Porkolab, Phys. Plasmas 16 , 082705 (2009)

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Mikhail A. Dorf, M.S.
Princeton University , Princeton , NJ
Princeton Plasma Physics Laboratory
Advisor: Ronald C. Davidson
Pursuing Ph.D. in Plasma Physics

Mikhail's research is focused on both analytical studies and advanced numerical simulations of intense charged particle beams transport and focusing for high energy density physics and heavy ion fusion applications. The topical areas of his research include, for example: intense beam transport through an alternating-gradient quadrupole lattice, including the development of a novel spectral technique that provides insights into the microstate of beam halo particles; and intense ion beam transport through a background neutralizing plasma along a solenoidal magnetic field, including collective streaming instabilities and effects of the beam charge and current neutralization.

Publications:

  1. M. Dorf, V.E. Semenov, V.G. Zorin, A Fluid Model for Ion Heating due to Ionization in a Plasma Flow , Phys. Plasmas 15 , 093501 (2008).
  2. M. A. Dorf, A. V. Sidorov, V. G. Zorin, A. F. Bohanov, A. V. Vodopyanov, I.V. Izotov, S. V. Razin, and V. A. Skalyga, Noise suppression and stabilization of an ion beam extracted from dense plasma, J. Appl. Phys. 102 , 054504 (2007).
  3. M. Dorf, R. C. Davidson and E. A. Startsev, Transverse Compression of an Intense Ion Beam Propagating through an Alternating-Gradient Quadrupole Lattice , Phys. Rev. ST Accel. Beams 9 , 034202 (2006).
  4. M. Dorf, A.V.Savilov, New method for generation of short high-power rf pulses, Phys. Rev. ST Accel. Beams 7 , 112001 (2004).
  5. M. Dorf, A.V. Savilov, Mutual Amplification of two Traveling Transverse Waveguide Modes Coupled by a Bragg Structure , Radiophys. Quant. Elect. 47 , 276 (2004).
  6. M. Dorf, I. Kaganovich, E. Startsev, and R. Davidson, Enhanced Self-Focusing of an Ion Beam Pulse Propagating Through a Background Plasma Along a Solenoidal Magnetic Field, submitted for publication in the Physics Review Letters (2009).
  7. M. Dorf, R. Davidson, E. Startsev , and H. Qin, Adiabatic Formation of a Matched-Beam Distribution for an Alternating-Gradient Quadrupole Lattice , submitted for publication in the Phys. Rev. ST Accel. Beams (2009).
  8. M. Dorf, R. C. Davidson, and E. A. Startsev, Particle-in-Cell Simulations of Halo Particle Production in Intense Charged Particle Beams Propagating Through a Quadrupole Focusing Field with Varying Lattice Amplitude , Proceedings of the 22 nd Particle Accelerator Conference, Albuquerque, NM (2007).
  9. M. Dorf, R. C. Davidson, E. A. Startsev, and H. Qin, Adiabatic Formation and Properties of a Quasi-Equilibrium Beam Distribution Mathced to a Periodic Focusing Lattice , submitted for publication in the proceedings of the 23 nd Particle Accelerator Conference, Vancouver , Canada (2009).
  10. E. Startsev, R. Davidson, and M. Dorf, Streaming instabilities of intense charged particle beams propagating along a solenoidal magnetic field in a background plasma , Phys. Plasmas 15 , 062107 (2008).
  11. A. Sidorov, M. Dorf, V. Zorin, A. Bokhanov, I. Izotov, S. Razin, V. Skalyga J. Roßbach, P. Spädtke A. Balabaev, Multiaperture ion beam extraction from gas-dynamic electron cyclotron resonance source of multicharged ions , Rev. Sci. Instrum. 79 , 02A317 (2008 ).
  12. R. C. Davidson, I. Kaganovich, E. A. Startsev, H. Qin, M. Dorf , A. Sefkow, D. R. Welch, D. V. Rose, S. M. Lund , Multspecies Weibel Instability for Intense Charged Particle Beam Propagation Through Background Plasma , Nucl. Instrum. Meth. Phys. Res. A 577 , 70 (2007).
  13. M. Chung, E.P. Gilson, M. Dorf, R. C. Davidson, P.C. Efthimion and R. Majeski, Experiments on Transverse Compression of a Long Charge Bunch in a Linear Paul Trap , Phys. Rev. ST Accel. Beams 10 , 064202 (2007).
  14. M. Chung, E. P. Gilson, M. Dorf, R. C. Davidson, P. C. Efthimion and R. Majeski, Ion Injection Optimization for a Linear Paul Trap to Study Intense Beam Propagation , Phys. Rev. ST Accel. Beams 10 , 014202 (2007).
  15. E. P. Gilson, M. Chung, R. C. Davidson, M. Dorf, D.P. Grote, P. C. Efthimion, R. Majeski and E. A. Startsev, Conditions for Minimization of Halo Particle Production During Transverse Compression of Intense Ion Charge Bunches in the Paul Trap Simulator Experiment (PTSX) , Nucl. Instrum. Meth. Phys. Res. A, 577 , 117 (2007).
  16. E. P. Gilson, M. Chung, R. C. Davidson, M. Dorf, P. C. Efthimion and R. Majeski, Experimental Simulations of Beam Propagation Over Large Distances in a Compact Linear Paul Trap , Phys. Plasmas 13 , 056705 (2006).
  17. E. P. Gilson, M. Chung, R. C. Davidson, M. Dorf, P. C. Efthimion, A. B. Godbehere, R. Majeski, Recent Advances In The Physics Of Collective Excitations In The Paul Trap Simulator Experiment, Nucl. Instrum. Meth. Phys. Res. in press (2009).
  18. R. C. Davidson, M. A. Dorf, I. D. Kaganovich, H. Qin, A. B. Sefkow, E. A. Startsev, D. R. Welch, D. V. Rose, and S.  M. Lund, Survey of Collective Instabilities and Beam-Plasma Interactions in Intense Heavy Ion Beams , Nucl. Instrum. Meth. Phys. Res. in press (2009).
  19. A. Friedman, J.J. Barnard, R.J. Briggs, R.C. Davidson, M. Dorf , D.P. Grote, E. Henestroza, E.P. Lee, M.A. Leitner, B.G. Logan, A.B. Sefkow, W.M. Sharp, W.L. Waldron, D.R. Welch, S.S. Yu, Toward a physics design for NDCX-II, an ion accelerator for warm dense matter and HIF target physics studies , Nucl. Instrum. Meth. Phys. Res. in press (2009).
  20. P.A. Seidl, A. Anders, F.M. Bieniosek, J.J. Barnard, J. Calanog, A.X. Chen, R.H. Cohen, J.E. Coleman, M. Dorf , E.P. Gilson, D.P. Grote, J.Y. Jung, M. Leitner, S.M. Lidia, B.G. Logan, P. Ni, P.K. Roy, K. Van den Bogert, W.L. Waldron, D.R. Welch, Progress in beam focusing and compression for warm-dense matter experiments , Nucl. Instrum. Meth. Phys. Res. in press (2009).

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Forrest William Doss
University of Michigan
DOE Stewardship Science Graduate Fellow
C.A.S.M. Applied Mathematics (Part III of the Mathematical Tripos)
Cambridge University, Cambridge, England
B.S. Physics
B.S.M.E. Mechanical Engineering
West Virginia University, Morgantown, WV
Pursuing Ph.D. Applied Physics

I am investigating structure in radiatively collapsed shocks. In the high-energy-density regime, radiative transport becomes significant, and the shocked layer collapses to high densities due to the emission of its thermal energy as radiation.  This work has identified a previously unobserved feature of strongly radiating systems. As  a radiating shock's speef increases, the corresponding radiation becomes strong enough to significantly heat the upstream shock tube wall, vaporizing the tube material some distance ahead of the primary shock. This drives a secondary, radially converging shock, named a wall shock. The resulting observed structure can be used as a diagnostic of dynamics.

Publications:

  1. "Wall shocks in high-energy-density physics", F.W. Doss, H.F. Robey, R.P. Drake, C.C. Kuranz, Physics of Plasmas (submitted)
  2. "Repeatability in radiative shock experiments", F.W. Doss, R.P Drake, C.C. Kuranz, High Energy Density Physics (submitted)

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Jay Fahlen, M.S.
University of California, Los Angeles
Advisor: Warren Mori
Pursuing Ph.D. in Electrical Engineering

Jay Fahlen's research uses particle-in-cell (PIC) computer simulations to study plasma waves and stimulated Raman scattering (SRS).  Many nonlinearities have been suggested as the mechanism for saturating the SRS instability, and he has studied several in detail.  Using electrostatic PIC simulations to replicate the plasma wave effects seen in fully electromagnetic SRS simulations, Jay is able to reduce the complexity of the problem to more manageable levels.  He has examined nonlinear plasma wave frequency shifts and the effects of trapped particles on finite-length wave packets.  He is currently working on understanding the behavior of large-amplitude plasma waves in multiple dimensions.

Publications:

  1. B.J. Winjum, J. Fahlen, and W.B. Mori, Phys. Plasmas 14, 102104 (2007).
  2. J.E. Fahlen, B.J. Winjum, T. Grismayer, and W.B. Mori, Submitted to PRL (2008).

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Jonathan Grava, M.S.
Colorado State University
Advisor: Jorge Rocca
Pursuing: Ph.D. in Electrical Engineering

Our group's research focuses on dense plasma diagnostics using short wavelength interferometry. Using a high energy short pulse laser, several different target geometries are irradiated, creating a hot (~100s eV) dense (~1e20 cm-3) plasma. This plasma is then probed with a 46.9 nm capillary discharge soft x-ray laser combined with a soft x-ray interferometer. Several interferograms are are taken, mapping the evolution of the plasma. Density maps inferred from the interferograms are then compared to 2D simulations, helping us understand the dynamics behind these plasmas.

Publications:

  1.  J. Filevich, J. Grava, M. Purvis, M.C. Marconi, J.J. Rocca*, *J. Nilsen, J. Dunn, and W.R. Johnson, “Prediction and observation of tin and silver plasmas with index of refraction greater than one in the soft x-ray range,” Physical Review E *74*, 016404, (2006).
  2. J. Filevich, J. Grava, M. Purvis,  M.C. Marconi, J.J. Rocca, J. Nilsen, J. Dunn, and W.R. Johnson, “Multiply ionized carbon plasmas with index of refraction greater than one,” Laser Particle Beams, *25*, 47, (2007).
  3. M. Purvis, J. Grava, J. Filevich, M.C. Marconi, J. Dunn, S.J. Moon, V.N. Shlyaptsev, E. Jankowska, and J.J. Rocca, “Dynamics of converging laser-created plasmas in semi-cylindrical cavities studied using soft x-ray laser interferometry,” Physical Review E, *76*, 046402, (2007).
  4.  J. Grava, M.A. Purvis, J. Filevich, M.C. Marconi, J.J. Rocca, J. Dunn, S.J. Moon, V.N. Shlyaptsev, “Dynamics of a dense laboratory plasma jet investigated using soft x-ray laser interferometry,” Physical Review E, *78*, 016403, (2008).
  5. J. Grava, M.A. Purvis, J. Filevich, M.C. Marconi, J. Dunn, S.J. Moon, V.N. Shlyaptsev, and J.J. Rocca, “Soft X-Ray Laser Interferometry of a Dense Plasma Jet”, IEEE Transactions on Plasma Sciences *36*, 4, 1286, (2008).
  6.  M. Purvis, J. Grava, J. Filevich, M.C. Marconi, J. Dunn, S.J. Moon, V.N. Shlyaptsev, E. Jankowska, and J.J. Rocca, “Soft x-ray laser interferometry of colliding laser-created plasmas in semi-cylindrical cavities,” IEEE Transactions on Plasma Sciences *36*, 4, 1134, (2008).
  7.  J. Nilsen, J.I. Castor, C.A. Iglesias, K.T. Cheng, J. Dunn, W.R. Johnson, J. Filevich, M.A. Purvis, J. Grava, and J.J. Rocca, “Understanding the anomalous dispersion of doubly-ionized carbon plasmas near 47 nm,” High Energy Density Physics *4*, 107, (2008).

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Tammy Ma , M.S.
University of California, San Diego
Lawrence Livermore National Laboratory
Advisor: Farhat Beg
Pursuing Ph.D. in Aerospace Engineering/Plasma Physics

Tammy 's research focuses on understanding some of the underlying physics of laser-plasma interactions and hot electron production and transport in cone geometries relevant to Fast Ignition.  Cone-guided Fast Ignition is an Inertial Confinement Fusion scheme in which a precompressed fuel target is driven to ignition by a fast "ignitor" laser pulse that is guided using a cone inserted into the pellet.   Tammy has participated in numerous experiments using the Titan Laser at LLNL and the RAL Petawatt Laser at the Rutherford Appleton Laboratory, U.K to investigate the effect of laser prepulse on energy coupling into cone and cone+wire targets.  The hybrid transport code Zuma and the particle-in-cell code LSP are used to translate experimental observables into estimates of hot electron production efficiency and transport.

Publications:

  1. Studies on the Transport of High Intensity Laser-Generated Hot Electrons in Cone Coupled Wire Targets J. A. King, K. U. Akli, R. R. Freeman, J. Green, S. P. Hatchett, D. Hey, P. Jamangi, M. H. Key, J. Koch, K. L. Lancaster, T. Ma , A. J. Mackinnon, A. MacPhee, P. A. Norreys, P. K. Patel, T. Phillips, R. B. Stephens, W. Theobald, R. P. J. Town, L. Van Woerkom, B. Zhang, and F. N. Beg Physics of Plasmas, 16 , 020701 (2009)
  2. Determination of Electron-Heated Temperatures of Petawatt Laser-Irradiated Foil Targets with 256 eV and 68 eV Extreme Ultraviolet Imaging T. Ma , A. G. MacPhee, M. H. Key, S. P. Hatchett, K. U. Akli, T. W. Barbee, C. D. Chen, R. R. Freeman, J. A. King, A. Link, A. J. Mackinnon, D. T. Offermann, V. Ovchinnikov, P. K. Patel, R. B. Stephens, L. D. Van Woerkom, B. Zhang, F. N. Beg. Review of Scientific Instruments, 79 , 093507 (2008) Also selected for the October 2008 issue of Virtual Journal of Ultrafast Science .
  3. Density Measurement of Shock Compressed Foam Using 2D X-ray Radiography Sebastien Le Pape, Andrew MacPhee, Daniel Hey, Pravesh Patel, Andy MacKinnon, Mike Key, John Pasley, Mingsheng Wei, Hui Chen, Tammy Ma , Farhat Beg, Rich Stephens, Dustin Offermann, Linn Van Woerkom, and Rich Freeman. Review of Scientific Instruments 79 , 106104 (2008)
  4. Electron Heated Target Temperature Measurements in Petawatt Laser Experiments based on Extreme Ultraviolet Imaging and Spectroscopy T. Ma , F. N. Beg, A. G. MacPhee, H.-K. Chung, M. H. Key, A. J. Mackinnon, P. K. Patel, S. Hatchett, K. U. Akli, R. B. Stephens, C. D. Chen, R. R. Freeman, A. Link, D. T. Offermann, V. Ovchinnikov, and L. D. Van Woerkom. Review of Scientific Instruments 79 , 10E312 (2008) Also selected for the November 2008 issue of Virtual Journal of Ultrafast Science
  5. Diagnostics for Fast Ignition Science A. G. MacPhee, K. U. Akli, F. N. Beg, C. D. Chen, H. Chen, R. Clarke, D. S. Hey, R. R. Freeman, A. J. Kemp, M. H. Key, J. A. King, S. Le Pape, A. Link, T. Y. Ma , H. Nakamura, D. T. Offermann, V. M. Ovchinnikov, P. K. Patel, T. W. Phillips, R. B. Stephens, R. Town, Y. Y. Tsui, M. S. Wei, L. D. Van Woerkom, and A. J. Mackinnon. Review of Scientific Instruments 79 , 10F302 (2008)
  6. Development of Backlighting Sources for a Compton Radiography Diagnostic of Inertial Confinement Fusion Targets R. Tommasini, A. MacPhee, D. Hey, T. Ma , C. Chen, N. Izumi, W. Unites, A. MacKinnon, S. P. Hatchett, B. A. Remington, H. S. Park, P. Springer, J. A. Koch, O. L. Landen, John Seely, Glenn Holland, and Larry Hudson Review of Scientific Instruments 79 , 10E901 (2008) Also selected for the November 2008 issue of Virtual Journal of Ultrafast Science
  7. Extreme Ultraviolet Imaging of Electron-Heated Targets in Petawatt Laser Experiments Tammy Ma , Andrew G. MacPhee, Michael H. Key, Kramer U. Akli, Troy W. Barbee, Jr., Andrew J. Mackinnon, Richard B. Stephens, Linn D. Van Woerkom, Bingbing Zhang, and Farhat N. Beg. IEEE Transactions on Plasma Science, Vol. 36, No. 4 (2008)
  8. Nail-Like Targets for Laser-Plasma Interaction Experiments J. Pasley, M. Wei, E. Shipton, S. Chen, T. Ma , F. N. Beg, N. Alexander, R. Stephens, A. G. MacPhee, D. Hey, S. Le Pape, P. Patel, A. Mackinnon, M. Key, D. Offermann, A. Link, E. Chowdhury, L. Van Woerkom, and R. R. Freeman. IEEE Transactions on Plasma Science, Vol. 36, No. 4 (2008)
  9. Laser Heating of Solid Matter by Light-Pressure-Driven Shocks at Ultrarelativistic Intensities K. U. Akli, S. B. Hansen, A. J. Kemp, R. R. Freeman, F. N. Beg, D. C. Clark, S. D. Chen, D. Hey, S. P. Hatchett, K. Highbarger, E. Giraldez, J. S. Green, G. Gregori, K. L. Lancaster, T. Ma , A. J. MacKinnon, P. Norreys, N. Patel, J. Pasley, C. Shearer, R. B. Stephens, C. Stoeckl, M. Storm, W. Theobald, L. D. Van Woerkom, R. Weber, and M. H. Key. Physical Review Letters, 100 , 165002 (2008)
  10. Fast Electron Generation in Cones with Ultraintense Laser Pulses L. Van Woerkom, K. U. Akli, T. Bartal, F. N. Beg, S. Chawla, C. D. Chen, E. Chowdhury, R. R. Freeman, D. Hey, M. H. Key, J. A. King, A. Link, T. Ma , A. J. MacKinnon, A. G. MacPhee, D. Offermann, V. Ovchinnikov, P. K. Patel, D. W. Schumacher, R. B. Stephens, and Y. Y. Tsui. Physics of Plasmas, 15 , 056304 (2008)
  11. Effect of Laser Intensity on Fast-Electron-Beam Divergence in Solid-Density Plasmas J. S. Green, V. M. Ovchinnikov, R. G. Evans, K. U. Akli, H. Azechi, F. N. Beg, C. Bellei, R. R. Freeman, H. Habara, R. Heathcote, M. H. Key, J. A. King, K. L. Lancaster, N. C. Lopes, T. Ma , A. J. MacKinnon, K. Markey, A. MacPhee, Z. Najmudin, P. Nilson, R. Onofrei, R. Stephens, K. Takeda, K. A. Tanaka, W. Theobald, T. Tanimoto, J. Waugh, L. Van Woerkom, N. C. Woolsey, M. Zepf, J. R. Davies, and P. A. Norreys. Physical Review Letters, 100 , 015003 (2008)
  12. Experimental Observations of Transport of Picosecond Laser Generated Electrons in a Nail-like Target J. Pasley, M. Wei, E. Shipton, S. Chen, T. Ma , F. N. Beg, N. Alexander, R. Stephens, A. G. MacPhee, D. Hey, S. Le Pape, P. Patel, A. Mackinnon, M. Key, D. Offermann, A. Link, E. Chowdhury, L. Van-Woerkom, and R. R. Freeman. Physics of Plasmas 14 , 120701 (2007)

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Michael A. Purvis, M.S.
Colorado State University
Advisor: Jorge J. Rocca
Pursuing Ph.D. in Electrical Engineering

Mike Purvis recently completed a 3 year fellowship with LLNL and continues to make progress towards a PhD at CSU. His group has conducted several soft x-ray interferometry experiments of dense plasmas using a 46.9nm capillary discharge laser at CSU. The measurements produce data that illustrates the evolution of plasmas created by intense laser irradiation of solid targets. He uses Livermore's code HYDRA to further understand these dense plasma experiments. Similar methods were employed to complete studies on a laborotory produced bow shock, the dynamics of laborotory plasma jets and the mechanisims responsible for jet collimation.

Publications:
  1. J. Nilsen, J.I. Castor, C.A. Iglesias, K.T. Cheng, J. Dunn, W.R. Johnson, J. Filevich, M.A. Purvis , J. Grava, and J.J. Rocca , “Understanding the anomalous dispersion of doubly-ionized carbon plasmas near 47 nm,” High Energy Density Physics 4 , 107, (2008).
  2. M. Purvis , J. Grava, J. Filevich, M.C. Marconi, J. Dunn, S.J. Moon, V.N. Shlyaptsev, E. Jankowska, and J.J. Rocca , “Soft x-ray laser interferometry of colliding laser-created plasmas in semi-cylindrical cavities,” IEEE Transactions on Plasma Sciences 36 , 4, 1134, (2008).
  3. J. Grava, M.A. Purvis , J. Filevich, M.C. Marconi, J. Dunn, S.J. Moon, V.N. Shlyaptsev, and J.J. Rocca, “Soft X-Ray Laser Interferometry of a Dense Plasma Jet”, IEEE Transactions on Plasma Sciences 36 , 4, 1286, (2008).
  4. J. Grava, M.A. Purvis , J. Filevich, M.C. Marconi, J.J. Rocca , J. Dunn, S.J. Moon, V.N. Shlyaptsev, “Dynamics of a dense laboratory plasma jet investigated using soft x-ray laser interferometry,” Physical Review E 78 , 016403, (2008).
  5. M. Purvis , J. Grava, J. Filevich, M.C. Marconi, J. Dunn, S.J. Moon, V.N. Shlyaptsev, E. Jankowska, and J.J. Rocca , “Dynamics of converging laser-created plasmas in semi-cylindrical cavities studied using soft x-ray laser interferometry,” Physical Review E, 76 , 046402, (2007).
  6. J. Filevich, J. Grava, M. Purvis , M.C. Marconi, J.J. Rocca , J. Nilsen, J. Dunn, and W.R. Johnson, “Multiply ionized carbon plasmas with index of refraction greater than one,” Laser Particle Beams, 25, 47, (2007).
  7. J. Filevich, J. Grava, M. Purvis , M.C. Marconi , J.J. Rocca, J. Nilsen, J. Dunn, and W.R. Johnson, “Prediction and observation of tin and silver plasmas with index of refraction greater than one in the soft x-ray range,” Physical Review E 74 , 016404, (2006).

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Derek Schaeffer, M.S.
University of California, Los Angeles
Advisor: Christoph Niemann
Pursuing Ph.D. in Plasma Physics

My research focuses on studying collisionless shocks relevant to astrophysical phenomena, such as coronal mass ejections, planetary bow shocks, and the expansion of supernova remnants.  Specifically, I use a Thomson scattering diagnostic to characterize (electron temperature and density, charge state, ion density) the plasma blowoff from a high-powered laser ablated target (usually carbon).  Thomson scattering is ideal because it is non-invasive, highly temporally and spatially resolved, and largely model-independent.  Data from such diagnostics will help to understand how collisonless shocks dissipate heat; what the density fluctuations inside such shocks look like; and how turbulence evolves in these shocks.

Publications:
  1. Constantin, C., Gekelman, W., Pribyl, P., Everson, E., Schaeffer, D., Kugland, N.,  Presura, R., Neff, S., Plechaty, C., Vincena, S., Collette, A., Tripathi, S., Villagram Muniz, M., Niemann, C., “Collisionless interaction of an energetic laser produced plasma with a large magnetoplasma,” Astrophys Space Sci 322, 155 (2009)
  2. Schaeffer, D., et al., AAS, DPS meeting #38, #61.11 (2006)

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