Population inversions in ablation plasmas generated by intense electron beams. Annual report, 1 November 1985-1 November 1986

Technical Report · Sun Nov 30 04:00:00 EST 1986

OSTI ID:6783255

Gilgenbach, R M; Kammash, T; Brake, M L

Experiments investigated the spectroscopic emission from electron-beam-driven carbon anode plasmas. Diode closure results in three phases of beam-plasma evolution which are summarized below: Stage I: Deposited electron dose is smaller than that required for anode plasma formation. No light is detected in this phase. Stage II: Deposited electron dose is large enough for anode plasma formation before the diode shorts. Spectroscopic data for noncrowbarred shots (dose approx = 500-800 J/g) indicate the presence of CII and CIII with a high level of background radiation. Stage III: Cathode plasma begins shorting A-K gap or anode and cathode plasmas meet. For crowbarred shots (dose > 300 J/g) molecular emission is observed from C/sub 2/ and CH. Atomic emissions from CII and H. Noncrowbarred shots exhibit intense atomic emission; at early times CIII and CII are the primary components; however emission from CIV has also been observed. Electron temperatures from Boltzmann plots are 2-3 eV. A second thrust of our experimental program has been a study of electron beam induced optical emission in helium. The main hydrodynamic assumption is that the plasma can be described using single-fluid and temperature equations. The Collisional-Radiative Equilibrium (CRE) model is used to describe the ionization dynamics of the system. This model consists of a set of rate equations, one for each quantum state included, which describe the effect of atomic processes on the population and depopulation of a given state. The final component of the theory is the energy-deposition model. The stopping power is based on a formalism for relativistic electrons interacting with a plasma which has both free and bound electrons.

• Research Organization: Michigan Univ., Ann Arbor (USA). Dept. of Nuclear Engineering
• OSTI ID: 6783255
• Report Number(s): AD-A-177367/0/XAB
• Country of Publication: United States
• Language: English

Related Subjects

640410* -- Fluid Physics-- General Fluid Dynamics
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABLATION
BACKGROUND RADIATION
BEAM-PLASMA SYSTEMS
BEAMS
BOLTZMANN EQUATION
CATHODES
CLOSURES
COLLISIONS
DIFFERENTIAL EQUATIONS
ELECTRODES
ELECTRON BEAMS
EMISSION SPECTRA
EMISSION SPECTROSCOPY
EQUATIONS
FLUIDS
IONIZATION
LEPTON BEAMS
MATHEMATICAL MODELS
PARTIAL DIFFERENTIAL EQUATIONS
PARTICLE BEAMS
POPULATION INVERSION
RADIATIONS
SPECTRA
SPECTROSCOPY
STOPPING POWER