An investigation of self-generated magnetic fields and electron emission in laser-produced plasmas
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Authors
Case, Roger Salisbury
Subjects
Advisors
Schwirzke, Fred R.
Gurenther, Arthur H.
Date of Issue
1974-03
Date
Publisher
Language
en_US
Abstract
An experimental study of magnetic signals from laserproduced
plasmas has been performed. From 2 to 30 joules of
laser energy impinged upon metallic and hydrocarbon targets
in pulse lengths of from 4 to 80 nanoseconds, and at incident
angles of 0° and 45°. Two magnetic signals were detected
using inductive probes; one whose peak intensity is
temporally coincident with, and whose rise time is a function
of the incident laser pulse length; the second longerlasting
and time-delayed from the arrival of the laser pulse
on target. The first signal results from electrons emitted
anisotropically from the laser-produced plasma. This emission
current is limited by space charge effects, and is
strongly dependent upon the ambient gas pressure over the
range of 10~ 6 to 10 +1 Torr. The second magnetic signal
arises from misaligned temperature and density gradients
within the laser plasma. The dependencies of these signals
on residual gas pressure, laser pulse length and shape, and
spatial location have been evaluated.
Type
Thesis
Description
Series/Report No
Department
Physics and Chemistry