Intense microwave pulse propagation through gas breakdown plasmas in a waveguide
High-power microwave pulse-compression techniques are used to generate 2.856 GHz pulses which are propagated in a TE/sub 10/ mode through a gas filled section of waveguide, where the pulses interact with self-generated gas-breakdown plasmas. Pulse envelopes transmitted through the plasmas, with duration varying from 2 ns to greater than 1 ..mu..s, and peak powers of a few kW to nearly 100 MW, are measured as a function of incident pulse and gas pressure for air, nitrogen, and helium. In addition, the spatial and temporal development of the optical radiation emitted by the breakdown plasmas are measured. For transmitted pulse durations greater than or equal to 100 ns, good agreement is found with both theory and existing measurements. For transmitted pulse duration as short as 2 ns (less than 10 rf cycles), a two-dimensional model is used in which the electrons in the plasma are treated as a fluid whose interactions with the microwave pulse are governed by a self-consistent set of fluid equations and Maxwell's equations for the electromagnetic field. The predictions of this model for air are compared with the experimental results over a pressure range of 0.8 torr to 300 torr. Good agreement is obtained above about 1 torr pressure, demonstrating that microwave pulse propagation above the breakdown threshold can be accurately modeled on this time scale. 63 refs., 44 figs., 2 tabs.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 7242247
- Report Number(s):
- UCRL-53764; ON: DE87002752
- Resource Relation:
- Other Information: Thesis. Portions of this document are illegible in microfiche products. Original copy available until stock is exhausted
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
MICROWAVE RADIATION
WAVE PROPAGATION
PLASMA
BREAKDOWN
DATA ACQUISITION SYSTEMS
ELECTRON DENSITY
EXPERIMENTAL DATA
TIME DEPENDENCE
WAVEGUIDES
DATA
ELECTROMAGNETIC RADIATION
INFORMATION
NUMERICAL DATA
RADIATIONS
700103* - Fusion Energy- Plasma Research- Kinetics