PLASMA ACCUMULATION IN A DEVICE FED BY ENERGETIC ION TRAPPING

Technical Report · Thu Nov 10 04:00:00 EST 1960

OSTI ID:4094022

Mackin, Jr, R J

Simon has given a general steady-state theory of plasma accumulation (without energy losses) in an OGRA device. Such a device is fed by the injection of energetic molocular ions which dissociate to produce trapped protons. Initial trapping is achieved by dissociation in the background gas. Such a device is usually characterized by a critical input current of critical plasma density (a function of input current) above which plasma density builds up to a value limited by Coulomb-scattering losses. For a regime of operation of current interest at Oak Ridge National Laboratory (600-kev hydrogen molecular ion injection and dissociation, highly efficient ion-pumping action of the trapped plasma), extremely simple approximate formulas were derived which describe with a fair degree of accuracy the critical current or density for plasma build-up. More accurate formulas were derived which describe overlapping segments of the density-current curve to about 10% for a broad range of parameters. In every case, simple expressions for the critical currents result. The analysis was applied to a system in which initial trapping is accomplished by a Luce carbon arc. Two new points emerge: (1) the critical current for plasma build-up with arc is less than previously estimated by nearly an order of magnitude if the arc is turned off slowly or if an arc of lower density is used; and (2) the critical arc density, below which plasma build-up occurs after the arc is removed, is sufficiently low that energy losses to fixed-temperature arc electrons are not significant. Also treated are the time dependence of plasma build-up, certain aspects of the impurity problem, and electron heating effects. Numerical examples are given for OGRA and DCX-2. (auth)

• Research Organization: Oak Ridge National Lab., Tenn.
• NSA Number: NSA-15-010202
• OSTI ID: 4094022
• Report Number(s): CF-60-11-50
• Country of Publication: United States
• Language: English

Related Subjects

BACKGROUND
CARBON
CRITICAL CURRENT
CURRENTS
DECOMPOSITION
DENSITY
ELECTRIC ARCS
ELECTRONS
ENERGY
ENERGY RANGE
GASES
HEATING
HYDROGEN
IMPURITIES
INJECTION
IONIZATION
IONS
LOSSES
MAGNETIC MIRRORS
MOLECULES
OGRA
PHYSICS
PLASMA
PROTONS
SCATTERING
THERMONUCLEAR DEVICES