Numerical Calculations of Magnetoacoustic Oscillations in Toroidal Plasmas

Magnetoacoustic oscillations in toroidal argon and hydrogen plasmas have been calculated numerically and compared with those in cylindrical plasmas. The toroidal plasmas show reduced enhancement at resonance and shifted resonant frequencies. The position of maximum enhancement of the oscillation fields at resonance which occurs on the minor axis of a large aspect ratio torus is displaced not only toward lower static B field values but also in a direction at right angles to ∇∣B∣ when the aspect ratio is small. As the frequency is increased to values, only moderately higher than resonance, the spatial distribution of the oscillation fields rapidly becomes more complicated than those for the cylindrical plasmas.