The special thing about 159 nm is that it is almost entirely absorbed by air and ionizing it. Ionized air can be affected by other radiation to be heated. Heating localized air around a body makes a push on it. I want to elaborate with propulsion of this kind.
UV with shorter wavelenght than 159 nm is called VUV, vacuum ultraviolet, since it can only exist in vacuum. It is absorbed by air. Very funny would be to have tunable UV on the border between UV and VUV. The absorption rate would then be adjustable and the radiation could pass arbitrarily far away ffrom the radiation source. I want to heat air around an object as described in my arXiv article on preventing shock waves. I think that the same technique can be used to achieve propulsion as well and it could be the way that flying saucers operate. They fly with apparently no moving parts and UV/VUV in combination with heating could have the same effect. I see that many vacuum UV lights can be bought: http://www.google.se/search?hl=en&q=vacuum+uv+lamp David David Jonsson, Sweden, phone callto:+46703000370
