  On the example of the exoplanet HD 189733 an influence of stellar activity on
the efficiency of the plasma mechanism of radio emission generation of the
exoplanet and the properties of this emission are considered. The plasma
generation mechanism can be effectively implemented in the plasmasphere of
exoplanets with a weak magnetic field and a relatively high electron plasma
density, when the electron cyclotron maser is not efficient. The plasma
mechanism depends essentially on the parameters of the plasma and involves the
generation of plasma waves by energetic electrons and a conversion of these
waves into electromagnetic radiation. The stellar wind can significantly modify
the exoplanet plasmasphere, which was not taken into account in the first
studies of the plasma mechanism in the plasmasphere of HD 189733b. In present
study we used a three-dimensional model of the interaction of the exoplanet
HD189733b with the stellar wind for cases of moderate and intense stellar
winds. The study shows that the implementation of plasma mechanism is possible
at any intensity of the stellar wind. However, depending on the intensity, the
requirements for the parameters of plasma mechanism change. In particular, the
plasma waves energy which is required to generate the radio emission available
for registration by modern radio telescopes changes. Besides, the frequency
range of the radio emission changes. The latter will make it possible to use
the detected radio emission as an indicator of the activity of the parent star.
