On the 90th anniversary of the Lebedev Physics Institute of the Russian Academy of Sciences (LPI)
Conditions for runaway electron generation in an air gap with an inhomogeneous electric field: theory and experimen
N.M. Zubareva,b,
G.A. Mesyatsa,
M.I. Yalandina,b aLebedev Physical Institute, Russian Academy of Sciences, Leninsky prosp. 53, Moscow, 119991, Russian Federation bInstitute of Electrophysics, Ural Branch of the Russian Academy of Sciences, ul. Amundsena 106, Ekaterinburg, 620016, Russian Federation
The conditions for the generation of runaway electrons (RAEs) in a magnetically insulated coaxial air diode with needle and conical, with the Taylor opening half-angle of 49.3°, graphite cathodes are compared. The axial magnetic field makes it possible to focus the RAE beam on the collector current probe, thereby increasing the sensitivity of the recording technique used. It has been established that the threshold voltage for RAE generation for the Taylor cone is lower than for the needle (i.e., the cone with a small opening angle), which indicates its non-monotonic angular dependence with a minimum occurring at an angle not exceeding the Taylor one. According to our estimates, the dynamics of free electrons changes qualitatively at the Taylor angle. At larger angles, they accelerate throughout the entire gap; at smaller ones, they accelerate near the cathode and then decelerate at the periphery.
Keywords: runaway electrons, air diode, inhomogeneous electric field, guiding magnetic field, pulsed breakdown, conical cathode, Taylor angle DOI:10.3367/UFNe.2023.11.039608 Citation: Zubarev N M, Mesyats G A, Yalandin M I "Conditions for runaway electron generation in an air gap with an inhomogeneous electric field: theory and experimen" Phys. Usp., accepted
Received: 9th, October 2023, revised: 15th, November 2023, accepted: 28th, November 2023