Fluid and kinetic aspects of magnetic reconnection and some related magnetospheric phenomena
- PDF / 15,576,412 Bytes
- 84 Pages / 439.37 x 666.142 pts Page_size
- 91 Downloads / 183 Views
Fluid and kinetic aspects of magnetic reconnection and some related magnetospheric phenomena L. C. Lee1,2,3 · K. H. Lee1,4 Received: 19 March 2020 / Accepted: 19 July 2020 © Division of Plasma Physics, Association of Asia Pacific Physical Societies 2020
Abstract Magnetic field reconnection plays a key role in determining the magnetic field topology and in the conversion of magnetic energy into kinetic energy in cosmic plasmas. Magnetic reconnection was proposed by solar physicists in an attempt to explain solar flares. The concept of magnetic reconnection was extended to Earth’s magnetosphere to explain auroral substorms. In this review, we first briefly review the classical fluid steady models with small separatrix angle. We then report magnetic reconnection with a large separatrix angle, and the time-dependent multiple X line reconnection (MXR) associated with flux transfer events. The transition from a single X line reconnection to MXR is examined. Global three-dimensional (3-D) magnetic reconnection is reviewed. The particle pressure gradient associated mainly with the electron (ion) off-diagonal pressure tensor terms, Pxy and Pzy , is shown to play an important role for electron (ion) dynamics to balance the reconnection electric field ( Ey ) near the X line. In addition, various plasma waves and instabilities may occur near the ion diffusion and electron diffusion regions, including the upper hybrid drift waves, lower hybrid drift waves, ion-ion beam instability, electron beam instability, whistler waves and kinetic Alfvén waves. The layered structure of outflow region of magnetic reconnection is examined. These layered structures include slow shocks, rotation discontinuities, expansion waves and plasma jets. Recent satellite observations of magnetic reconnection in the Earth and planetary magnetospheres are also discussed. The polar cap electric field associated with magnetic reconnection at the Earth’s magnetopause and the energy flow in the polar cap region are examined. Keywords Two- and three-dimensional magnetic reconnections · Off-diagonal pressure tensor · Small and large separatrix angles · Multiple X line reconnection (MXR) · Polar cap electric field from reconnection · Poynting energy flow
* L. C. Lee [email protected] * K. H. Lee [email protected] Extended author information available on the last page of the article
13
Vol.:(0123456789)
9
Page 2 of 84
Reviews of Modern Plasma Physics
(2020) 4:9
1 Introduction Magnetic field reconnection plays an important role in determining the topology of magnetic fields and in the conversion of magnetic energy into kinetic energy in cosmic plasmas. The concept of magnetic reconnection was originally proposed by Giovanelli (1946). This idea was then developed by solar physicists in 1950s in an attempt to explain solar flares (Parker 1957; Sweet 1958), which require an energy supply as much as 1027 − 1028 erg/s for each event in the lower part of the solar atmosphere. Thus the energy observed must be stored in some form prior to so
Data Loading...
