A contribution to the streamer breakdown criterion

The streamer breakdown criterion, ∫α¯dx=K, has been used for more than half a century. The magnitude of K is believed to be equal to 18 for all gases. Throughout this period of time however, various changes have been made to both the interpretation of the streamer breakdown criterion and the magnitude of K. It has been pointed out that the magnitude of K is approximately about 10, not 18 as previously believed. Such a high value of the magnitude of K=18, as believed in the past can essentially contribute to erroneous effective ionisation coefficients