Evidence of filamentation (self-focusing) of a laser beam propagating in a laser-produced aluminium plasma
Abstract
The thresholds for self-focusing of a laser beam in a laser-produced plasma computed for propagation of a nanosecond duration pulses in short, high density multiply ionized absorbing plasmas are reported. Theoretical treatment of self-focusing used a computational model TRSF (Siegrist, 1976) to calculate the self-focusing behavior of a laser beam which is Gaussian in time and space and propagating through a multiply ionized absorbing plasma initially of uniform density and temperature. The self-focusing thresholds for aluminum, carbon, and deuterium as a function of electron temperature, and of 400 eV aluminum plasma as a function of plasma density were obtained. Measurement of laser and plasma parameters and observations of filamentary structures in the X-ray emission from aluminum plasmas accompanied by an increase in the divergence of the light transmitted through them are discussed. It was shown that self-focusing has occurred at an intensity near to that predicted by the computer code, in approximately 10 to the 13th to 10 to the 14th W per sq cm for nanosecond duration pulses in plasmas formed by irradiating light solids.
- Publication:
-
Journal of Physics D Applied Physics
- Pub Date:
- August 1979
- DOI:
- 10.1088/0022-3727/12/8/005
- Bibcode:
- 1979JPhD...12.1261D
- Keywords:
-
- Aluminum;
- Dense Plasmas;
- Electron Energy;
- Laser Beams;
- Laser Plasma Interactions;
- Metallic Plasmas;
- Self Focusing;
- Computer Programs;
- Light Transmission;
- Plasma Density;
- Plasma Diagnostics;
- Plasma Radiation;
- Pulse Duration;
- X Ray Spectroscopy;
- Lasers and Masers