HR: 14:40h
AN: NG33A-05    [Abstracts]
TI: Experimental Study of the Nonlinear Evolution of Plasma Filaments
AU: * Katz, N
EM: nkatz@mit.edu
AF: MIT Plasma Science & Fusion Center, 167 Albany St, Cambridge, MA 02139, United States
AU: Egedal, J
EM: jegedal@psfc.mit.edu
AF: MIT Plasma Science & Fusion Center, 167 Albany St, Cambridge, MA 02139, United States
AU: Fox, W
EM: willfox@mit.edu
AF: MIT Plasma Science & Fusion Center, 167 Albany St, Cambridge, MA 02139, United States
AU: Le, A
EM: arile@mit.edu
AF: MIT Plasma Science & Fusion Center, 167 Albany St, Cambridge, MA 02139, United States
AU: Porkolab, M
EM: porkolab@psfc.mit.edu
AF: MIT Plasma Science & Fusion Center, 167 Albany St, Cambridge, MA 02139, United States
AB: We investigate experimentally the nonlinear motion and structure of toroidally symmetric plasma filaments propagating through neutral gas. Propagating structures, often denoted `blobs', have been observed in diverse plasmas ranging from the low-latitude F region of the ionosphere [1] to the edge of many magnetically-confined laboratory plasmas [2]. We use the Versatile Toroidal Facility (VTF), a well-diagnosed basic plasma physics experiment, to study blobs systematically. We observe for the first time the characteristic mushroom shape of the blob, which is predicted from nonlinear simulations [3]. Furthermore, we measure the internal electrostatic structure and show that the blob propagation velocity is inversely proportional to the background neutral density. Further evidence that the neutrals provide drag on the blob is given by measurements showing that the electron temperature decreases as the plasma loses energy to the neutrals. [1] Park J et al, Geophys. Res. Lett. 30 (2003) 2114 [2] Zweben S et al, Nucl. Fusion, 44 (2004) 134 [3] Garcia O et al, Phys. Plasmas, 12 (2005) 090701 Work supported by DOE Junior Faculty Award DE-FG02-06ER54878. N. Katz partly funded by a Fusion Energy Sciences Fellowship, administered by ORISE. W. Fox and N. Katz partly funded by CMPD Award DE-FC02- 04ER54786.
DE: 2463 Plasma convection (2760)
DE: 2760 Plasma convection (2463)
DE: 7839 Nonlinear phenomena (4400, 6944)
DE: 7859 Transport processes
SC: Nonlinear Geophysics [NG]
MN: 2007 Fall Meeting