JOVIAN MAGNETOSPHERIC ION-CYCLOTRON INSTABILITY IN THE PRESENCE OF PARALLEL ELECTRIC-FIELD

A dispersion relation for left hand circularly polarized electromagnet ic wave propagation in an anisotropic magnetoplasma in the presence of a very weak parallel electrostatic field has been derived with the he lp of linearized Vlasov and Maxwell equations. An expression of the gr owth rate has been derived in presence of parallel electric field for ion-cyclotron electromagnetic wave in an anisotropic media. The modifi cation made in the growth rate by introducing parallel electric field and temperature anisotropy has been studied for fully ionized hydrogen plasma with the help of observations made on Jovian ionosphere and ma gnetosphere at L = 5.6 R(j). It is concluded that the growth (damping) of ion-cyclotron electromagnetic wave is possible when the wave vecto r is parallel (antiparallel) to the static electric field and effect i s more pronounced at higher wave number.