HIF 2010
18th International Symposium
on Heavy Ion Inertial Fusion -
Information

Title:	Dr.
Family Name:	Startsev
First Name:	Edward
E-Mail:	estartspppl.gov
Affiliation for Badge:	Princeton University
Institute:	Princeton Plasma Physics Laboratory
Address (Street):	Sayre Drive, PO box 451
Postal Code, City:	Princeton, NJ 08543
Country:	United States
Phone:	16092433511
Fax:	12432418
Payment:	Bank transfer to GSI
Author(s):	E. A. Startsev, R. C. Davidson and V. N. Khudik
Institute(s):	Plasma Physics Laboratory, Princeton University, Princeton, New Jersey, 08543 USA University of Texas, Austin, Texas, 78712 USA
Title:	Stability properties of the electron return-current for intense ion beam propagation through background plasma*
Abstract:	When an intense ion beam propagates through a dense background plasma, its current is partially neutralized by the electron plasma return current. Due to the non-uniformity of the background plasma electrons velocity profile $V_z^e(r)$, the flow can be unstable. The instability is similar to the Kelvin-Helmholz instability for the non-uniform flow of an incompressible neutral fluid, with the electrostatic potential playing the role of pressure. For the case of electron return current flow, the significant new feature is the presence of the partially neutralized self-magnetic field of the ion beam, which significantly affects the evolution of small-amplitude excitations. In this paper the stability properties of the flow of electrons making up the plasma return current is investigated using the macroscopic cold-fluid-Maxwell equations. It is shown that this flow may become unstable, but the instability growth rates are exponentially small. The body mode has a maximum growth rate for beams with radius of order the collisionless electron skin depth, $r_b\sim c/\omega_{pe}$. This unstable body mode is qualitatively different from previously studied surface-mode excitations of the electron plasma return current for an intense ion beam with a sharp radial boundary, which is found to be stable due to the stabilizing influence of the partially neutralized magnetic field of the ion beam [1]. [1] E. A. Startsev, R. C. Davidson and M. Dorf, Physics of Plasmas 16, 092101 (2009).
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