Hypothetic Explanation of Peculiar Atmospheric Electric Response to SEP at High Latitudes. Experimental Evidence.

Measurements of atmospheric electric characteristics which have been conducted at high geomagnetic latitudes during several strong solar proton events with ground-level enhancements include in each case a long time interval of unusually large (twice or bigger) increase of the vertical electric current Jz in stratosphere, or of the atmospheric electric field Ez at surface.Since these enhancements are not transient variations they demonstrate presence of an additional electric circuit superimposed to the global atmospheric electric circuit during SPE.An explanation is proposed based on the following processes: i) positive charge injection into polar atmospheric regions Rp; ii) gradual, yet eventually dramatic decrease of conductivity in Rp due to aerosol increase.This explanation is confirmed by rocket-borne data for electric characteristics in stratosphere and mesosphere during a major solar proton event.Experimentally determined characteristics of peculiarity in cases S1,2, G1,2.We characterize the peculiarity represented by (1) in each of cases S1,2, G1,2 by the time interval t of the peculiar increase of Jz or Ez, and the maximum deviation Jzmax or Ez during t, similarly to (Tonev and Asenovski, 2023).In case S1 (Holzworth et al., 1987) we study the variations of current Jz=Ez at altitude 26 km at two balloon stations located at: a) (44.6S, 142.7E) with invariant latitude = 56.3 (cutoff rigidity 1.4 GV); b) (38.7S, 65.7E),