title: Relativistic electrons from sparks in the laboratory.
abstract: Discharge experiments were carried out at the Eindhoven University of Technology in 2013. The experimental setup was designed to search for electrons produced in meter-scale sparks using a 1 MV Marx generator. Negative voltage was applied to the high voltage (HV) electrode. Five thin (1 mm) plastic detectors (5 cm2each) were distributed in various configurations close to the spark gap. Earlier studies have shown (for HV negative) that X-rays are produced when a cloud of streamers is developed 30-60 cm from the negative electrode. This indicates that the electrons producing the X-rays are also accelerated at this location, that could be in the strong electric field from counterstreamers of opposite polarity. Comparing our measurements with modeling results, we find that ∼300 keV electrons produced about 30-60 cm from the negative electrode are the most likely source of our measurements. A statistical analysis of expected detection of photon bursts by these fiber detectors indicates that only 20%-45% of the detected bursts could be from soft (∼10 keV) photons, which further supports that the majority of detected bursts are produced by relativistic electrons.
authors.affiliation: Birkeland Centre for Space Science, Department of Physics and Technology University of Bergen Bergen Norway.
authors.forename: N
authors.initials: N
authors.lastname: Østgaard
authors.affiliation: Birkeland Centre for Space Science, Department of Physics and Technology University of Bergen Bergen Norway; Department of Physics Carthage College Kenosha Wisconsin USA.
authors.forename: B E
authors.initials: BE
authors.lastname: Carlson
authors.affiliation: Birkeland Centre for Space Science, Department of Physics and Technology University of Bergen Bergen Norway.
authors.forename: R S
authors.initials: RS
authors.lastname: Nisi
authors.affiliation: Birkeland Centre for Space Science, Department of Physics and Technology University of Bergen Bergen Norway.
authors.forename: T
authors.initials: T
authors.lastname: Gjesteland
authors.affiliation: Birkeland Centre for Space Science, Department of Physics and Technology University of Bergen Bergen Norway.
authors.forename: Ø
authors.initials: Ø
authors.lastname: Grøndahl
authors.affiliation: Birkeland Centre for Space Science, Department of Physics and Technology University of Bergen Bergen Norway.
authors.forename: A
authors.initials: A
authors.lastname: Skeltved
authors.affiliation: Birkeland Centre for Space Science, Department of Physics and Technology University of Bergen Bergen Norway.
authors.forename: N G
authors.initials: NG
authors.lastname: Lehtinen
authors.affiliation: Birkeland Centre for Space Science, Department of Physics and Technology University of Bergen Bergen Norway.
authors.forename: A
authors.initials: A
authors.lastname: Mezentsev
authors.affiliation: Birkeland Centre for Space Science, Department of Physics and Technology University of Bergen Bergen Norway; INAF-IASF National Institute for Astrophysics Bologna Italy.
authors.forename: M
authors.initials: M
authors.lastname: Marisaldi
authors.affiliation: Birkeland Centre for Space Science, Department of Physics and Technology University of Bergen Bergen Norway; Department of Electric Engineering Technische Iniversiteit Eindhoven Eindhoven Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: Kochkin
keywords: X‐rays; laboratory; relativistic electrons; sparks