| Abstract : | Plasma waves are observed in almost all the solar system objects - planets, their satellites, comets, Sun, interplanetary medium, etc. The planetary ionospheres are capable of sustaining plasma waves which are observed there and play an important role in the ionospheric dynamics by propagating energy across different space regions and provide acceleration to particles to attain high energies for transportation. The study of planetary plasma waves also provides information on the solar wind – planet interaction, the energy distribution in the ionospheric plasma of that planet, etc.
Venus does not possess a global magnetic field unlike Earth. The solar EUV radiation ionizes the neutrals and generates a plasma environment around Venus which can sustain plasma waves. Very few attempts are made to observe all plasma waves that can exist around Venus and that too with instruments having a limited dynamic range such as with PVO (Pioneer Venus Orbiter) and Venus Express. However, there are some other plasma waves which can exist around Venus but are yet to be observed. ISRO is planning to send an orbiter mission to Venus is near future where a suit of instruments named VIPER is included onboard to observe plasma waves around Venus.
The proposed scientific instruments in VIPER, are – a customized Langmuir probe to measure the electron and ion number density and electron and ion plasma temperature; a triaxial electric field sensor to measure the oscillating plasma wave electric field; a triaxial fluxgate magnetometer to measure the background magnetic field and a triaxial search-coil magnetometer to measure the oscillating plasma wave magnetic field. The information from all these four instruments shall be combined to detect and observe Venusian plasma waves.
The detailed scientific objectives of this plasma wave observation experiment near Venus and the methodology to achieve this shall be discussed in this paper. |
