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2R/300HJ

Fig. 4.7.3. The same as in Fig. 4.7.1 but for j = 3.

It can be seen from Fig. 4.7.1-4.7.3 that the scattering by inhomogeneities of types j = 1, 2, and 3 is characterized by a rapid decrease of 9 both with increasing R (as « R-1, « R-2, « R-3, respectively, for inhomogeneities of types j = 1, 2, and 3, and with decreasing R when 2rL/l = 2R/300Ho l < 1 for j = 1, 2R/300Ho l < 0.8 for j = 2, and 2R/300Hol < 0.7 for j = 3. The latter circumstance essentially differs the scattering by inhomogeneities of types j = 1, 2, and 3 from the scattering by magnetic clouds (in which at R > 300hol 9<x R 2, but at R < 300hol the angle 9> 1

and the value of 9 is practically independent on R at R^0). It follows from Eq. 4.7.3 that for the inhomogeneities of types j = 1, 2, and 3 the scattering angle 9(r) exhibits a peak maximum at

According to Eq. 4.7.4 we obtain 2Rmax/300Hol = 1, 0.816, 0.707 for j = 1, 2, and 3, respectively. The small angle scatterings seem to be fairly frequent in the space; in particular, they will also take place during charged particle interactions with the plasma pulsations and the disturbances of various types (see in more detail in Chapters 1 and 2). It is obvious that the smaller the scattering angle 9 is smaller the change of particle energy AE (in the extreme when 9 ^ 0, it should be that AE ^ 0).

4.7.2. Energy gain in head-on and overtaking collisions in non-relativistic case for small angle scatterings

In order to estimate the mode of energy change for small angle scattering, we shall examine first the simplest example, namely a head-on collision of non-relativistic particle with magnetic cloud (see Fig. 4.7.4).

Fig. 4.7.4. A scheme of determination of the particle velocity change during non-mirror interactions for head-on collisions.

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