Research of ns-timescale electrical discharge in pressurized gases

TYPEPlasma Physics
Speaker:Shurik Yatom
Location:Lidow 620
Remark:PhD seminar
Abstract:This talk outlines the main experimental results regarding the research of nanosecond time-scale discharge in gases as air, H2 and He2, conducted at P≥105 Pa. Discharges were ignited in gas filled chambers, with interelectrode gap ≤3cm, by application of high-voltage (HV) pulses ≤200 kV in amplitude and duration ≤5ns at FWHM to a blade cathode. The discharge is ignited by runaway electrons (RAE), responsible for pre-ionization of the gas, thus allowing for the discharge to develop during single nanoseconds. In the last 4 years we have investigated this discharge using a variety of non-disturbing diagnostics with temporal resolution close to a single nanosecond: fast-framing imaging, x-ray foil spectroscopy, electron beam imaging, electron beam foil spectroscopy, optical emission spectroscopy and Coherent anti-Stokes Raman Scattering. Profound conclusions were drawn regarding the dynamics of the discharge and dependence on the gas and pressure, energy spectrum of RAE and the x-ray radiation, RAE emission mechanism, plasma parameters such as electron density and temperature, intensity of electric fields present in the plasma channels and conductivity of the discharge plasma.