D.c. breakdown characteristics of gaseous helium in uniform and non-uniform electric fields down to 4.2 K at atmospheric pressure have been investigated. Although helium is a nonelectronegative gas, a negative pulse corona is observed only near the normal boiling point due to the abrupt appearance of quasi-bubble state electrons. Positive ion space charge modifies the electric field distribution in the gap space considerably. The electric field strength on the non-corona electrode in the ion flow field is measured satisfactorily and analysed theoretically using a numerical electric field calculation technique. On the basis of experimental results, methods are proposed to give corona onset criteria and the breakdown voltage preceded by a positive glow corona.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Physics and Astronomy(all)