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Effective critical electric field for runaway-electron generation.
A Stahl1, E Hirvijoki1, J Decker1,2
1Department of Applied Physics, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
Physical Review Letters
|April 4, 2015
Summary
The effective electric field for runaway-electron generation in plasmas is often higher than previously thought due to temperature dependence and synchrotron losses. This impacts understanding of plasma physics and high-energy particle dynamics.
Area of Science:
- Plasma Physics
- Kinetic Theory
Background:
- Runaway-electron generation is crucial in plasma physics.
- Previous calculations of the critical electric field may be underestimated.
Purpose of the Study:
- Investigate factors influencing the effective critical electric field for runaway-electron generation.
- Clarify the threshold electric field for significant runaway-electron formation.
Main Methods:
- Numerical solutions of the kinetic equation.
- Analysis of primary generation dependence on temperature.
- Inclusion of synchrotron radiation losses.
Main Results:
- The effective electric field is often higher than previously calculated.
- Temperature dependence and synchrotron losses increase the required electric field.
- Elevated effective critical field is mainly due to momentum-space distribution changes.
Conclusions:
- Runaway-electron generation is sensitive to plasma temperature and energy loss mechanisms.
- Previous estimates of the critical electric field require revision.
- Experimental observations of elevated critical fields are explained by momentum-space dynamics.
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