The influence of the magnetic field shear is studied on the E × B (and/or gravitational) and the Current Convective Instabilities (CCI) occurring in the high‐latitude F layer ionosphere. It is shown that magnetic shear reduces the growth rate of these instabilities. The magnetic shear‐induced stabilization is more effective at the larger‐scale sizes (≥ tens of kilometers) while at the scintillation causing intermediate scale sizes (∼ a few kilometers), the growth rate remains largely unaffected. The eigenmode structure gets localized about a rational surface due to finite magnetic shear and has broken reflectional symmetry due to centroid shift of the mode by equilibrium parallel flow or current.

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Second harmonic heating experiments using fast waves are carried out on the Aditya tokamak in the ion cyclotron resonance frequency (ICRF) range with the help of a 200 kW, 20-40 MHz RF heating system, which is developed indigenously. Significant direct electron heating is observed in a hydrogen plasma. The rise in electron temperature is prompt with the application of RF power and the increment in electron temperature increases linearly with RF power. A corresponding increase in plasma beta and hence an increase in stored diamagnetic energy are also observed in the presence of RF power. The low-Z impurity radiation and electron density do not increase significantly with RF power. The direct electron heating by fast wave in Aditya is also predicted by the ion cyclotron resonance heating code TORIC.

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