EFFICIENCY ESTIMATES FOR CONVERSION OF FOCUSED LASER RADIATION TO X RAYS IN A HOT DENSE PLASMA,
Abstract
The report examines the feasibility of using focused laser radiation to generate a dense high-temperature plasma in the keV range that will reradiate a significant amount of the absorbed energy as high energy photons. The difficulty is that the plasma expands more rapidly as the temperature is increased, thereby diminishing the plasma radiation rate, which depends on the free electron density. The total radiation will be on the order of two to three times that of bremsstrahlung alone and will consist primarily of photon energies that are less than an energy corresponding to the plasma temperature. For a temperature of several keV, the plasma will expand within a few tenths of a nanosecond, requiring that the lasers have equally short pulses for optimum use of the laser energy. The frequencies of Nd-glass lasers and ruby lasers correspond to maximum electron densities of about 1 to 2 X (10 to the 21st power)/(cu cm), and estimates place the emitted x radiation at around 1 to 2% of the energy absorbed in a fraction of a nanosecond. Use of frequency-doubling crystals or creation of high-power ultraviolet lasers would increase the efficiency by up to an order of magnitude. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1968
- Accession Number
- AD0672964
Entities
People
- Gerald G. Comisar
- Melvin J. Bernstein
Organizations
- The Aerospace Corporation