Pinch Phenomena in a Flash X-ray Discharge

The discharges were performed in a coaxial flash x-ray tube (voltage = 15 kv, pressure = 10^-5 to 10^-6 mm Hg and inductance = 75 × 10^-9 h) provided with a plane parallel electrode system. The discharge process has been studied by oscillographic recordings of any pair of the three quantities: current, its time derivative and x-ray output, inside the time interval during which the heavy current pulse (peak current about 25 ka) occurs in the discharge. The production of both single and multiple x-ray outputs of short duration (0.1 μsec or less) is discussed and seems to be caused by pinch phenomena occurring in a plasma column between the tube electrodes. Small changes in dI/dt during the pinching are interpreted as sausage instabilities which cause high local rates of increase in inductance giving a potential drop (V = I dL/dt) across each constriction of the discharge. Estimation of the accelerating voltage during the pinching showed that it could reach values almost four times as high as the applied initial capacitor voltage. In order to get the timing of the x-ray outputs under better control, a new method for discharge initiation is suggested.

Print ISSN

0361-4573

Published

1964-04

Content type

Original Research

DOI

10.5594/J07259