**Abstract:** This work extends upon previous publication, Bachelor's thesis, which
described unrelativistic motion of an electron in a storm cloud, which was
represented by homogenous electric field, along with element of friction,
Chandrasekhar function. In a short time, observed electron was accelerated
to the relativistic speeds. In storm clouds, sometimes R-waves occur when
high-frequency electromagnetic wave passes through the plasma with magnetic
field. These waves rotate right-handed along field lines, same as fast
electron. Therefore, element describing interaction between electromagnetic
R-wave and given electron was introduced into the motion equation, presented
in this work.

Because this is clearly a relativistic problem, several attempts were made
at creating special relativistic motion equation this year, all of them
unsuccessful. Finding the element of friction, which is represented by
Chandrasekhar function in classical physics, has proven to be very
problematic, perhaps even impossible.