Thunderstorms as the probable reason of high background neutron fluxes at L<1.2

Abstract In this paper we analyze the neutron background fluxes measured in experiments on board MIR orbital station (1991), ISS (2002) and Kolibri-2000 satellite (2002) at an altitude of 400 km. The spatial distribution of high background neutron fluxes has a longitude dependence. The most intensive near-equatorial fluxes were recorded in the regions of Africa and the Pacific ocean. We assess the possibility that the occurrence of high background neutron fluxes in these regions is connected with lightning discharges. The observed neutron fluxes at an altitude of 400 km indicate that ∼10 10 neutrons are required to be produced by lightning discharge.