A NEW EXPRESSION FOR CYLINDRICALLY-SYMMETRICAL MAGNETIC-FIELDS IN CORONAL MAGNETIC LOOPS

We present a set of cylindrically-symmetric force-free magnetic fields with non-constant scalar function scalar alpha. We found that the kin k instability of the fields can be suppressed by reducing the length o f the flux tube. By using the pressure profile in coronal magnetic loo ps obtained on the basis of the observational data, and by neglecting the effect of gravity, these force-free fields ars modified to non-for ce-free ones. For the plasma of finite conductivity the time and space dependent magnetic fields are obtained, and the ohmic dissipation per unit volume per second is calculated. For the magnetic fields, presen ted in the investigation, it is also found that, due to the large elec trical conductivity of the plasma, the ohmic dissipation is negligable in comparison to the conduction and the radiation loss. Hence, for th e energy equilibrium in a coronal loop, the contribution of ohmic diss ipation is insignificant.