Lightning electromagnetic pulse penetration into the night‐time lower ionosphere and plasma modification are simulated using the large particle method. The collisions of the electrons with the neutral species, both elastic and related to the excitation, ionization of and attachment to the neutrals are modeled using a Monte‐Carlo technique. The dynamics of the impulse electron heating and breakdown in the lower ionosphere above the strong lightning discharge are analysed. The level of the induced ionization strongly depends on the amplitude, form and duration of the incident pulses. The selfconsistent fields on the time scale of 10² µs are subjected to strongly nonlinear damping during the passage through the D‐region of the ionosphere.

An optical system that comprises two devices for remote measurements, a broadband optical interferometer and a scanning Hartmann sensor, is described. The results of simultaneous measurements with both devices and the results of numerical modeling of sample surface heating are presented.

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The Interhelioprobe mission aims to investigate the inner heliosphere and the Sun from close distances (up to 0.3 AU) and from out of the ecliptic plane (up to 30°). In this paper we present the relevance of the mission and its main scientific objectives, describe the scientific payload, ballistic scenario and orbits of the spacecraft. Possibilities of scientific cooperation with other solar and heliospheric space missions are also mentioned.

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