HR: 0800h
AN: SM51B-05 INVITED     [Abstracts]
TI: Current Filament Merging Driven by Cross-Field Plasma Flows
AU: * Vincena, S
EM: vincena@physics.ucla.edu
AF: University of California, Los Angeles, 1000 Veteran Avenue Room 15-70, Los Angeles, CA 90095, United States
AU: Gekelman, W
EM: gekelman@physics.ucla.edu
AF: University of California, Los Angeles, 1000 Veteran Avenue Room 15-70, Los Angeles, CA 90095, United States
AU: Collette, A
EM: collette@physics.ucla.edu
AF: University of California, Los Angeles, 1000 Veteran Avenue Room 15-70, Los Angeles, CA 90095, United States
AU: Cooper, C
EM: cmc86@physics.ucla.edu
AF: University of California, Los Angeles, 1000 Veteran Avenue Room 15-70, Los Angeles, CA 90095, United States
AB: The study of the penetration and mixing of plasmas with differing density, temperature, and species composition has wide-ranging applicability to space plasma systems such as coronal mass ejections, magnetic clouds, galactic jets, and super novae. In these laboratory experiments, two high-beta plasmas are created using a pair of 1.5J, 8ns lasers which strike facing solid carbon targets at right angles to the background magnetic field. The targets are immersed within a low-beta, helium plasma and the lasers are aimed to produce head-on, or glancing collisions. The cylindrical background plasma is 17 m long (10 parallel Alfven wavelengths) by 60 cm wide (300 ρ_i or 175 c/ω_pe). The laser-produced plasmas (LPPs) expand as diamagnetic cavities, become polarized, and then E× B drift at speeds of Mach 10 (v/c_s) across the field. As they do so, the ambient plasma facilitates charge separation between energetic LPP electrons and relatively unmagnetized 1keV LPP ions. One of the many resulting dynamic features is the release of a continuous stream of electrons from each LPP. Downstream from the LPP merging, the fast electron current filaments come together with reconnection-like X-line field patterns and eventually merge with a broadband spectrum of electromagnetic (whistler wave) fluctuations. Near-miss LPP collisions result in elongated current sheet formations and the shedding of magnetic field eddies. Current sheet thicknesses are a few electron inertial lengths and the width is approximately one ion inertial length. These results will be presented along with 3D measurements of the magnetic fields and the underlying current systems. These experiments are conducted at the Basic Plasma Science Facility, in the upgraded Large Plasma Device (LAPD) located at the University of California, Los Angeles, USA. This work is funded by the United States Department of Energy and the National Science Foundation.
UR: http:plasma.physics.ucla.edu/bapsf
DE: 2111 Ejecta, driver gases, and magnetic clouds
DE: 2721 Field-aligned currents and current systems (2409)
DE: 7831 Laboratory studies and experimental techniques
DE: 7835 Magnetic reconnection (2723, 7526)
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Joint Assembly