Townsend's first ionization coefficients in crossed electric and magnetic fields in nitrogen

Townsend's first ionization coefficient (αT) in crossed electric and magnetic fields has been measured in nitrogen over the range of 140 ≤ E/p ≤ 360 volts cm−1 torr-1 and E/p ≤ 650 Oe torr−1. A coaxial cylinder geometry has been employed to avoid diffusion losses in the Ē.× H¯ direction. The initial photoelectric current is obtained by making the ultra-violet radiation obtained in an auxiliary glow discharge fall on the cathode of the coaxial cylinder geometry. Prebreakdown currents in the range of 10−12 − 10−9 amps are measured using the pressure variation technique of Townsend's experiment. The results of Bagnall and Haydon (1965), and Heylen and Bunting (1969) overlap with the present results over a relatively small range of E/p and E/p. Using the equivalent pressure concept the electron molecule collision frequency γ has been derived for the above range of E/p and E/p. It has been observed that γ changes with E/p at a constant E/p and also that γ changes as a function of E/p at a constant E/p. The transverse drift velocity for electrons in crossed fields has been derived from the measured Townsend first ionization coefficient.