FAST MAGNETIC-FIELD PENETRATION INTO A CYLINDRICAL PLASMA OF A NONUNIFORM DENSITY

The penetration of a magnetic field into a cylindrical plasma of a den sity that varied both radially and axially is studied. The magnetic fi eld penetrates rapidly due to the Hall field, along constant nr2 lines (n is the dimensionless plasma density and r is the dimensionless rad ial coordinate). For a plasma that conducts between two cylindrical el ectrodes, it is shown that there is magnetic field penetration for bot h positive and negative polarity cases as long as there is penetration along the electrodes. The magnetic field evolution is found, analytic ally and numerically, for different time behaviors of the magnetic fie ld at the boundaries. Ion velocities are also calculated.