On the generation of supershort avalanche electron beams and x radiation during nanosecond discharges in dense gases (results and discussion)

Abstract

Results of investigations of the generation of subnanosecond runaway electron beams and x radiation in gas diodes at elevated pressures are presented. The energy distributions of runaway electron beams generated in air at atmospheric pressure and the amplitude and duration of beam current pulses downstream of the foil have been measured, and also the mechanism of generation of a runaway electron beam has been analyzed. To record the beam current pulses, a collector which provided ~50-ps time resolution and a Tektronix TDS6604 real-time oscilloscope were used in the experiment. It has been shown that the new experimental data and model predictions confirm in the main the results earlier obtained at the Institute of High Current Electronics of the Russian Academy of Sciences Siberian Division. Evidence is cited that the key statements of L. P. Babich are erroneous.

Generation of super-short avalanche electron beams in SF6

“…The measuring elements were connected to the oscilloscope via RadioLab 5D-FB PEEG coaxial pulse cables with standard N-type connectors and Barth Electronics 142-NM attenuators with a bandwidth up to 30 GHz. Note that the SAEB parameters and spatial discharge images in air and nitrogen at negative polarity of voltage pulse were investigated in detail earlier Kostyrya et al, 2012;Shao et al, 2012;2013;Tarasenko, 2011;Tarasenko et al, 2004;2005;2007;2008a;2008b;Zhang et al, 2010;2013; see also Mesyats et al, 2006;2011). Super-short electron beams in SF 6 333…”

“…This error of estimation of the electron energy in air (Babich & Loiko, 1985) and SF 6 (Babich & Loiko, 1991) and/or voltage across the gap as well as incorrect description of the generation mechanism of RAE beams was repeated in publications of this scientific group, including in the monograph (Babich, 2003), within 20 years. However, as shown Tarasenko, 2011;Tarasenko et al, 2005;2007;2008a;2008b;2013b), the runaway electron beam downstream of the foil anode consisted of two or three groups of electrons of different energies and the number of electrons with anomalous energy was not more than 10% . No RAEs with anomalous energy in atmospheric air were detected, like in the study by Mesyats et al (2011), and the energy of RAEs was assumed not to exceed eU m under any conditions.…”

“…However, in 2003, about a 10-fold increase in the number of RAEs and amplitude of the beam current was observed by the Institute of High Current Electronics (IHCE) (Alekseev et al, 2003;Tarasenko et al, 2003). Note that the main data on the generation of RAEs and X-rays obtained until 2003 are reported (Babich, 2003), and analysis of various RAE measuring techniques, including those used by IHCE, is given elsewhere (Kostyrya et al, 2010;2012;Tarasenko et al, 2007;2008a;2008b;2008c;Tarasenko, 2011).…”