ИСТИНА

We consider the characteristic time, T, of the exponential decay of proton and electron SEP events (Ер few МeV, Ее few hundred keV), J = Jo exp (-t/T), Jo=10 - 10 4 (сm 2 s sr МeV) -1 and define the sectors of homogeneity in the inner heliosphere as regions where T is nearly constant. It is pointed out that in many events T = const for a period of 3-5 days, sometimes up to a week, that corresponds to the spread of the sector of homogeneity up to about 90 ̊. Sometimes the interval of homogeneity may extend to two, three or more successive SEP events with equal T, which suggests spatial homogeneity over longer time intervals, sometimes two weeks and even longer (then the spread of the sector of homogeneity is >180 ̊). This means that more than the half of near- Sun space has quasi-stationary characteristics of magnetic field and its fluctuations, or satisfies the stability of convection and adiabatic deceleration conditions, governing particle motion and providing the invariance of T. Such wide spread regions of homogeneity derived simultaneously from both p and e decays are observed only in about 50% of all events. In many cases one can find quasi stable interplanetary medium either for p or e, which suggests that only those parts of the spectrum of magnetic field fluctuations are invariable which correspond either to high (e) or low (p) frequencies throughout these periods. All exponential SEP event p and e decays are examined from this aspect using CPME instrument data aboard IMP-8 in 1974-2001.