Laser plasma particle velocities

Experiments were performed on laser produced plasma from aluminum target discs in a vacuum chamber at pressures a few times 10(-6) torr. Plasma analysis was achieved using a floating double electrostatic probe of tungsten wires biased at -15 volts DC. In analyzing 376 oscilloscope trace pictures of the probe signal, four velocity signals occurred with regularity. The plasma velocities detected by the probe were determined to be 3.7 X 10(7) cm/sec, 1.5 X 10(7)CM/Sec, 5.6 X 10(6) cm/sec (the bulk of the plasma) and 4.o X 10(6) cm/sec. A fifth, very fast signal at 1,0 X 10(6)cm/sec was also detected but it was not consistently present. Investigation of the velocity distributions as a function of time showed them not to be Boltzmann distributions, but exponential power distributions. Investigation of the crater formed by each laser pulse resulted in the determination of the following crater dimensions: crater depth 0.01 cm/shot, crater diameter of 0.11cm and a total spot size diameter of 0.70 cm for the laser-target interaction.

Department dc:contributor.department

Department of Physics and Chemistry

Year dc:date.issued

1976

Author dc:creator

• Callahan, Daniel James

Advisor dc:contributor.advisor

• Schwirzke, Fred R.

Statement dc:rights

• This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.

Language dc:language.iso

en_US

Handle dc:identifier.uri

https://hdl.handle.net/10945/17834

OAI identifier oai:identifier

oai:calhoun.nps.edu:10945/17834