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Quantitative, comprehensive, analytical model for magnetic reconnection in Hall magnetohydrodynamics
1Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Physical Review Letters
|October 15, 2008
Summary
A new theory explains fast magnetic reconnection independent of dissipation, crucial for understanding plasma dynamics. It reveals reconnection rates strongly depend on ion inertial lengths.
Area of Science:
- Plasma physics
- Astrophysics
- Space physics
Background:
- Magnetic reconnection is a fundamental process in plasma physics, crucial for phenomena like solar flares and geomagnetic storms.
- Previous models often assumed dissipation-dependent reconnection, limiting their applicability.
- Hall magnetohydrodynamics (MHD) and electron MHD have suggested dissipation-independent reconnection, but lacked a comprehensive theory.
Purpose of the Study:
- To develop the first quantitative analytical theory for dissipation-independent magnetic reconnection.
- To provide expressions for reconnection rates applicable to arbitrary ion inertial lengths.
- To establish a formal criterion for fast reconnection.
Main Methods:
- Developed a two-dimensional analytical theory for the magnetic reconnection diffusion region.
- Derived expressions for reconnection rates based on dissipation parameters and ion inertial lengths.
- Formally derived a criterion for fast reconnection.
Main Results:
- The theory quantitatively describes dissipation-independent magnetic reconnection.
- Reconnection rates are shown to depend strongly on the ion inertial length (d{i}).
- Confirmed that both open and elongated diffusion regions support fast reconnection, consistent with electron MHD predictions.
Conclusions:
- The proposed theory offers a unified framework for understanding fast magnetic reconnection across various scales.
- The strong dependence of reconnection rates on d{i} highlights its importance in astrophysical and laboratory plasmas.
- This work bridges the gap between computational observations and analytical predictions of fast magnetic reconnection.
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