Observation of resistive and ferritic wall modes in a line-tied pinch

The resistive wall mode is experimentally identified and characterized in a line-tied, cylindrical screw pinch when the edge safety factor is less than a critical value. Different wall materials have been used to change the wall time and show that the growth rates for the RWM scale with wall time and safety factor as expected by theory. The addition of a ferritic wall material outside the conducting shell leads to growth rates larger than the observed RWM and larger than theoretical predictions for the ferritic wall mode.