No abstract

It is shown that destabilization of resistive wall magnetohydrodynamic (MHD) modes in the presence of rotation is a mode coupling phenomenon. Based on this observation, certain unanticipated effects are readily explained. These include the fact that resistive wall modes with rotation can be unstable, even for parameters for which the MHD modes are stable with the wall at infinity, and the fact that this destabilization depends critically on the plasma parameters.

The coaxial plasma accelerator is a simple, compact, and mechanically robust device that utilizes the Lorentz J×B force to accelerate plasma to high velocity. Originally developed in the 1950s for the purpose of providing energetic plasmas for fusion energy experiments, coaxial plasma accelerators are presently being investigated as an environmentally sound and economical means of materials processing and advanced manufacturing. While commercial applications of this technology are already on line, future commercial applications will require improving accelerator reproducibility and efficiency, better controlling the accelerated plasma flow velocity or energy, and better controlling the distribution of directed energy or power on target. In this paper, the magnetohydrodynamic flow physics of magnetically nozzled plasma accelerators is presented with a view to achieving the accelerator control necessary for future industrial applications. Included is a fundamental description of plasma production, acceleration, and flow in a magnetic nozzle.

FormApproved OMB No.0704-0188 1a. REPORT SECURITY CLASSIFICATION uNCLASSIFIED 2a.SECURITY CLASSIFICATION AUTHORITY 2b. DECLASSIFICATION/ DOWNGRADING SCHEDULE 4. PERFORMING ORGANIZATION REPORT NUMBER(S) 6a. NAME OF PERFORMING ORGANIZATION Los Alamos National Laboratory EcADDRESS (City, State, and ZIP Coda) P.Oo BOX 1663 Los Alaxnos NM87545 6b. OFFICE SYM80L (If app//cab/e) 3a. NAME OF FUNDING I SPONSORING 8b. OFFICE SYMBOL ORGANIZATION {If applicable) 3?. ADDRESS (City, State, and ZIP Code) '