So, say it's 1990, and you're Danny Stillman, director of the technical intelligence division at Los Alamos National Laboratory, and you're visiting the Shanghai Institute of Nuclear Research (SINR) in China, and some of the friendly chaps there hand you some 35mm photos that show huge weird domes of light blossoming over northern China, near Soviet missile ranges. And they ask you "So, Danny, what do you think these are?"
The correct answer is: "I have no freaking idea."
One not-improbable answer: plasma shields (a CCCP fave) or even Tesla Domes ; much like the jolly Nazi scientific strides (ICBMs, jet fighters, etc.) made in the closing act of World War Deux, the Soviet military machine was undertaking some pretty fantastic work at the end of the Cold War (to keep up with American awesomosity).
The caption for the above photo, from Physics Today and Stillman's laugh-a-minute book The Nuclear Express: A Political History of the Bomb and its Proliferation:
Such domes expanded very rapidly, at around 3 km/s, with the centers remaining quite transparent. They stopped appearing in mid-1991. Could the light domes have been related to testing a defense system against incoming missiles? Could they result from self-destruct mechanisms on the missiles? To this day the origins of the domes of light are classified top secret in Russia. Outsiders know only two things for certain: The dome phenomena happened, and no one in the West really knows why.