Editing Magnetic reconnection (section)

===Non-MHD process: Collisionless reconnection===

On length scales shorter than the ion inertial length <math>c / \omega_{pi}</math> (where <math>\omega_{pi} \equiv \sqrt{\frac{n_i Z^2 e^2}{\epsilon_0 m_i}}</math> is the ion plasma frequency), [[ion]]s decouple from electrons and the magnetic field becomes frozen into the electron fluid rather than the bulk plasma.  On these scales, the [[Hall effect]] becomes important.  Two-fluid simulations show the formation of an X-point geometry rather than the double Y-point geometry characteristic of resistive reconnection.  The [[electron]]s are then accelerated to very high speeds by [[Electromagnetic electron wave|Whistler waves]].  Because the ions can move through a wider "bottleneck" near the current layer and because the electrons are moving much faster in Hall MHD than in [[Magnetohydrodynamics|standard MHD]], reconnection may proceed more quickly.  Two-fluid/collisionless reconnection is particularly important in the Earth's magnetosphere.