Структура и динамика полярных токовых систем : материалы международного симпозиума «Полярные геомагнитные явления», 25-31 мая, Суздаль, СССР / Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т. – Апатиты : [б. и.], 1988. – 150 с.

J.Buchner, L.M.Zeleny A NEW VIEW ON EXPLOSIVE SUBSTORM ONSET: CHAOTIC PARTICLE DYNAMICS AND EXCITATION OP THE TEARING MODE INSTABILITY ABSTRACT. We propose a new mechanism w h i c h in the c o r r e c t w a y describes the destabilization of the magnetospheric t a i l i n the c a u s e of t h e energy storage process and, therefore, the onset of i s o t a t e d s u b s t o r m s . A determinis­ tic chaotization of the electron motion h a s b e e n found to enforce a special kind of tearing mode instability. As it is well known, during the magnetic e n e r g y s t o r a g e in the substorm's growth phase the plasmasheet becomes more and m o r e c o m p r e s s e d , while the curv­ ature of the strongly streched field lines in the reversal r e g i o n increases. This leads to a strong coupling between the Larmor rotation and the longitud­ inal degree of freedom and, finally, to deterministic chaos in the electron motion. The subsequent nonadiabatic response of electrons to magnetic field perturbations was shown to create spontaneously a new neutral line. Our theory predicts the moment of isolated substorm onset by means of a simple numerical parameter which provides the key to a correct interpretation of experimental facts. The investigation of substorm explosions has an old and controversial history. Now the scientific community broadly accepts the opinion that one must differenciate between, at least, two main ways to a substorm onset: particularly a substorm may be triggered - with only small time delay - by a sudden change of the IMP (see, for example, /1 , 2/). But the substorm expansion can also appear spontaneously, after a period of slow evolution of the Earth's magnetotail, characterised by an enhanced magnetic and plasma energy transfer into the magnetosphere /3/. Recent experimental results provide rather firm reasons for this so called storage-unloading concept (see, e.g. /4/ or the CDAW-6 results discussed by Baker et al. /5/). The main problem in this scenario is to explain the sudden disruption of the previously continuous energy storage and to find the mechanism that is responsible for a spontaneous magnetotail instability. Many efforts have been undertaken in the past, to solve the problem of magnetotail destabilization. Por the first time Coppi et al. /6/ analyzed the stability of collisionless plasma in 1-dimensional magnetic field reversals in a Harris (1962)-type equilibrium (see Pig.1a). They found that such structure is unstable and a во-called tearing mode immediately begins to grow (see Pig.1b). But an important feature of the magnetic field in the Earth's magneto­ tail is the presence of a perpendicular to the "neutral" plane directed field component Вд^0 (see Pig.2a). After consideration of this fact in the framework of a kinetic stability analysis Galeev 0nd Zeleny showed that in contrary to a 1-dimensional equilibrium such 2-dimensional magnetic plasma confinement is very stable against tearing mode perturbations /7/. This result was later 70