Generation of runaway electrons and X-ray emission during breakdown of atmospheric-pressure air by voltage pulses with an ∼0.5-μs front duration

Journal Article · Sun Mar 15 04:00:00 EDT 2015 · Plasma Physics Reports

DOI:https://doi.org/10.1134/S1063780X15030058· OSTI ID:22472417

Kostyrya, I. D.

Results are presented from experiments on the generation of runaway electron beams and X-ray emission in atmospheric-pressure air by using voltage pulses with an ∼0.5-μs front duration. It is shown that the use of small-curvature-radius spherical cathodes (or other cathodes with small curvature radii) decreases the intensity of the runaway electron beam and X-ray emission. It is found that, at sufficiently high voltages at the electrode gap (U{sub m} ∼ 100 kV), the gap breakdown, the formation of a spark channel, and the generation of a runaway electron beam occur over less than 10 ns. At high values of U{sub m} behind the anode that were reached by increasing the cathode size and the electrode gap length, a supershort avalanche electron beam with a full width at half-maximum (FWHM) of up to ∼100 ps was detected. At voltages of ∼50 kV, the second breakdown regime was revealed in which a runaway electron beam with an FWHM of ∼2 ns was generated, whereas the FWHM of the X-ray pulse increased to ∼100 ns. It is established that the energy of the bulk of runaway electrons decreases with increasing voltage front duration and is ⩽30 keV in the first regime and ⩽10 keV in the second regime.

• OSTI ID: 22472417
• Journal Information: Plasma Physics Reports, Journal Name: Plasma Physics Reports Journal Issue: 3 Vol. 41; ISSN PPHREM; ISSN 1063-780X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
AIR
ANODES
BREAKDOWN
CATHODES
ELECTRIC DISCHARGES
ELECTRIC POTENTIAL
ELECTRON BEAMS
EMISSION
KEV RANGE
RUNAWAY ELECTRONS
SPHERICAL CONFIGURATION
X RADIATION