49th Annual Meeting of the Division of Plasma Physics
Volume 52, Number 11
Monday–Friday, November 12–16, 2007;
Orlando, Florida
Session TI2: Plasma Technology, Nozzles, and the First Wall
9:30 AM–12:30 PM,
Thursday, November 15, 2007
Rosen Centre Hotel
Room: Salon 3/4
Chair: David Ruzic, University of Illinois
Abstract ID: BAPS.2007.DPP.TI2.5
Abstract: TI2.00005 : Magnetic Nozzle and Plasma Detachment Scenario*
11:30 AM–12:00 PM
Preview Abstract
Abstract
Author:
Boris Breizman
(Institute for Fusion Studies, The University of Texas at Austin)
Some plasma propulsion concepts rely on a strong magnetic field
to guide the plasma flow through the thruster nozzle. The
question then arises of how the magnetically controlled plasma
can detach from the spacecraft. This talk presents a
magnetohydrodynamic detachment scenario in which the plasma
stretches the magnetic field lines to infinity [1]. Such a
scenario is of particular interest for high-power thrusters. As
plasma flows along the magnetic field lines, the originally
sub-Alfv\'enic flow becomes super-Alfv\'enic: this transition is
similar to what occurs in the solar wind [2]. In order to
describe the detachment quantitatively, the ideal MHD equations
have been solved analytically for a plasma flow in a slowly
diverging nozzle. The solution exhibits a well-behaved transition
from sub- to super- Alfv\'enic flow inside the nozzle and a
rarefaction wave at the edge of the outgoing flow. The magnetic
field in the detached plume is almost entirely due to the plasma
currents. It is shown that efficient detachment is feasible if
the nozzle is sufficiently long. In order to extend the
detachment model beyond the idealizations of analytical theory, a
Lagrangian fluid code has been developed to solve steady-stated
MHD equations and to optimize nozzle efficiency by adjusting the
magnetic coil configuration. This numerical tool enables broad
parameter scan with modest computational requirements (single
workstation). The code has been benchmarked against the idealized
analytical picture of plasma detachment and then used to
investigate more realistic nozzle configurations that are not
analytically tractable. Most recently, the code has been used to
interpret experimental data from the Detachment Demonstration
Experiment (DDEX) [3] facility at NASA Marshall Space Flight
Center. In collabotation with: M. Tushentsov, A. Arefiev, R.
Bengtson, J.Meyers (University of Texas at Austin),
D. Chavers, C. Dobson, J. Jones (Marshall Space Flight Center),
B.Schuettpelz,
(University of Alabama in Huntsville),
C. Deline
(University of Michigan).
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[1] A. Arefiev and B. Breizman,Phys. Plasmas {\bf12}, 043504 (2005).
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[2] E. N. Parker, Astrophys. J.{\bf128}, 664 (1958).
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[3] D. Chavers et al., ``Status of Magnetic Nozzle and Plasma
Detachment Experiment,'' CP813, Space Technology and Applications
International Forum, pp. 465-473, AIP 2006.
*Work supported by US DOE , NASA, and Ad Astra Rocket Company.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.DPP.TI2.5