Quasiadiabatic description of nonlinear particle dynamics in typical magnetotail configurations

Abstract

Abstract. In the present paper we discuss the motion of charged particles in three different regions of the Earth magnetotail: in the region with magnetic field reversal and in the vicinities of neutral line of X-and O-types. The presence of small parameters (ratio of characteristic length scales in and perpendicular to the equatorial plane and the smallness of the electric field) allows us to introduce a hierarchy of motions and use methods of perturbation theory. We propose a parameter that plays the role of a measure of mixing in the system.

Acceleration and transport of ions in turbulent current sheets: formation of non-maxwelian energy distribution

“…Such trajectory is called "Speiser" or transient orbit (Speiser, 1965). In addition to Speiser orbits in such "regular" configuration there are also fully trapped particles with circular orbits and quasi-trapped particles in CS (Speiser, 1965;Chen and Palmadesso, 1986;Buechner and Zelenyi, 1989;Vainchtein et al, 2005). On the other hand, an electric field E y pointing duskward appears in the CS as a result of interaction of the Earth's magnetosphere with the magnetized flow of the solar wind.…”

“…Some mechanism of particle acceleration in limited spatial regions (such as planetary magnetospheres and the solar corona) like the famous Fermi acceleration mechanism (Fermi, 1949) is needed to explain the formation of power tail (f ∼ε −1−κ ) of energy distribution and presence of groups of particles with large energy values (ε ε ). Different possible mechanisms were proposed such as acceleration near the CS X-line (Hoshino, 2005;Pritchett, 2006;Drake et al, 2006), ion acceleration by electric field due to the growth of tearing instability (Zelenyi et al, 1984;, quasiadiabatic ion acceleration in the vicinity of the magnetotail neutral sheet by the dawn-dusk electrostatic electric field (Speiser, 1967;Lyons and Speiser, 1982;Ashour-Abdalla et al, 1993, Litvinenko andSomov, 1993;Vainchtein et al, 2005;Zelenyi et al, 2007), particle acceleration by MHD turbulence in the solar corona (Kobak and Ostrowski, 2000;Dmitruk et al, 2004), acceleration due to dipolarization in the Earth's magnetosphere (Delcourt and Sauvaud, 1994;Delcourt, 2002;Apatenkov et al, 2007;Ono et al, 2009). In this paper we suggest another possible mechanism of acceleration which can operate in dynamic regions of CS.…”

Ion motion in the current sheet with sheared magnetic field – Part 2: Non-adiabatic effects

“…If J dyn = 0 (s = 0 case), then the averaged jump is equal to zero, but ( J dyn ) 2 ∼ κ 2 is finite. Thus, we need time ∼ κ −3 to change the invariant value substantially (the situation is different in the special case of when an initial value of I z is comparable with κ; see Vainshtein et al, 1999;Vainchtein et al, 2005). In the case of non-zero average value J dyn = 0 (s = 0 case) there is a drift in the space of the invariants.…”

“…Another class contains systems where a spatial scale of the magnetic field inhomogeneity is much smaller than a particle's Larmor radius. In this case the so-called theory of the quasi-adiabatic motion is used (Büchner and Zelenyi, 1986;Büchner and Zelenyi, 1989;Chen, 1992;Vainchtein et al, 2005;Zelenyi et al, 2013).…”

Preferential acceleration of heavy ions in the reconnection outflow region

“…As a result, trapped particles can move along the curved magnetic field lines. However, this motion does not result in escape from the resonance (see Vainchtein et al 2005;Artemyev et al 2013b). According to numerical modeling (e.g.…”