Soft X-ray gain in hydrogenic ions: Line pumping, ionization pumping and transient excitation
✍ Scribed by David G. Goodwin; Ernst E. Fill
- Publisher
- Springer
- Year
- 1990
- Tongue
- English
- Weight
- 976 KB
- Volume
- 50
- Category
- Article
- ISSN
- 0721-7269
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✦ Synopsis
In a plasma containing hydrogenic ions which is irradiated by appropriate X-ray radiation, gain on the n= 3~n= 2 (Balmer-~) transition can be generated. Depending on the spectrum of the pump radiation, there are two different ways of obtaining the inversion: direct excitation of the upper laser level by line radiation, or ionization of the hydrogenic ions by broad band radiation with subsequent population of the upper level by recombination.
In the first part of this paper, we present numerical calculations which compare the two pumping methods. The gain is evaluated under idealized conditions, i.e., with a pump spectrum containing only radiation useful for generating an inversion and under more realistic conditions, with a pump spectrum containing radiation at other frequencies as well.
In the second part of the paper the possibility of obtaining Balmer-~ gain in hydrogenic ions under highly transient conditions is investigated, assuming a pump pulse with a duration comparable to the decay time of the lower laser level. Considerable gain is predicted even for a black-body pump spectrum.