Beam-plasma discharge during the long-pulse REB injection in rarefied gas

Numerical simulation results of the interaction of a long-pulse relativistic electron beam (REB) with a slightly ionized middle pressure (p ∼ 1 Tor) gas in conditions of the beam-plasma discharge without external magnetic field are presented The next beam and plasma parameters were used in calculations: beam density nb = 10¹⁰ cm⁻³, beam radius a = 0.5 cm, particles energy W = 0.3 MeV, pulse duration τ = 50 µs, front duration τf = 1 µs, initial air plasma temperature Teo = 0.15 e V, initial plasma density Neo = 10¹¹ cm⁻³, system length L = 100 cm. The dissipative beam-plasma instability develops and the beam-plasma discharge ignites already in the current pulse front. To the moment t = 5 µs the beam-plasma discharge has turned to the quasi-stationary state, characterized by the level of the HF electric fields E ∼ 1 kV/cm. almost homogeneous distribution of the temperature Te ≈ 2 eV and inhomogeneous distribution of the plasma density ne. In time the gas heating takes place, mainly owing to the heat produced by the dissociative recombination of the plasma electrons and ions. Gas temperature Tg increases from the room value to Tg ≥ 10³ K.