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Updated: Dec 24, 2025
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Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry
Published on: August 1, 2017
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Electron temperature of the solar wind.
Stanislav Boldyrev1,2, Cary Forest3, Jan Egedal3
1Department of Physics, University of Wisconsin-Madison, Madison, WI 53706; boldyrev@wisc.edu.
Summary
Solar wind electrons exhibit a slower temperature decline than predicted by adiabatic theory. A new kinetic model explains this non-adiabatic expansion, revealing a universal regime for magnetized plasma winds.
Area of Science:
- Space Physics
- Plasma Physics
- Astrophysics
Background:
- Solar wind is a weakly collisional plasma expanding into diverging magnetic fields.
- Observed electron temperature decline in the inner heliosphere is slower than adiabatic expansion predicts.
Purpose of the Study:
- Develop a kinetic theory for non-adiabatic plasma expansion.
- Explain the observed slower-than-adiabatic electron temperature decline in solar wind.
Main Methods:
- Focus on energetic electron dynamics in diverging magnetic flux tubes.
- Analyze beam formation and energy transfer in nearly collisionless plasma.
Main Results:
- Energetic electrons form beams collimated along magnetic field lines.
- Weak energy exchange leads to electron beam energy loss and background plasma heating.
- A universal expansion regime is established at large distances, matching observations.
Conclusions:
- The kinetic theory explains the non-adiabatic electron temperature decline in solar wind.
- This model may describe magnetized collisionless winds from G-type stars.
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