Negative corona discharge in liquid helium

Conductivity and ionization mechanisms in liquid helium have been investigated by using high field conduction phenomena occurring near a sharp needle electrode. When the voltage V applied between the needle and the plane is greater than some threshold voltage V_s, a corona-like discharge regime was observed. Charge carriers are generated in the high field region close to the point where an intense light emission is detected. Above V_s the mean current is space charge limited and the mobility of charge carriers has been deduced from analysis of current-voltage characteristics. Some parameters of the corona-like region have been deduced from a spectral analysis of the light emitted during the discharge