Mixed Sustained and Self-Sustained Discharge Mechanism in Shock-Ionized Argon

Journal Article · Wed Jan 01 04:00:00 EST 1964 · Physics of Fluids (New York)

DOI:https://doi.org/10.1063/1.1711032· OSTI ID:4105471

Dällenbach, W.

The electric discharge in dense plasmas such as those obtained in shock tube experiments is investigated theoretically. Assuming that the positive ion saturation current density is of the order of the positive ion random current density, it is shown that quite high current densities are possible in dense plasmas, without an electron emission at the cathode being required. For instance, current densities up to 1000 amp/cm² are possible in argon at a temperature of 15,000 deg K and a pressure of 1 atm. It is then shown that the positive ion mean free path is in general much larger than the positive space charge sheet near the cathode. Hence the positive ions may be accelerated by the cathode voltage drop. Since their accommodation coefficient is smaller than 1, they keep part of their kinetic energy after neutralization, and the additionally can heat up the plasma in the vicinity of the cathode. This self-sustained discharge mechanism, which represents a thermal breakdown of the plasma layer near the cathode, reduces the cathode voltsge drop and limits the current density to a higher value.

• Research Organization: Battelle Memorial Inst., Geneva
• Sponsoring Organization: USDOE
• NSA Number: NSA-18-007813
• OSTI ID: 4105471
• Journal Information: Physics of Fluids (New York), Journal Name: Physics of Fluids (New York) Journal Issue: 1 Vol. 7; ISSN 0031-9171; ISSN PFLDAS
• Publisher: American Institute of Physics
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ARGON
BREAKDOWN
CATHODES
DENSITY
DIFFUSION LENGTH
ELECTRIC DISCHARGES
ELECTRIC POTENTIAL
ELECTRONS
EMISSION
HIGH TEMPERATURE
IONIZATION
PLASMA
SHOCK WAVES
THERMODYNAMICS