Ion sound effects on magnetic islands

The stability of rotating magnetic islands in homogenous plasmas is studied taking into account the ion polarization current and ion sound effects. Coupling to the ion sound dynamics occurs due to the modification of the ion plasma density that is no longer a function of the magnetic flux surfaces when the ion polarization drift is included. It is shown that while the ion polarization current is destabilizing, the ion sound effects turn out to be stabilizing in homogenous plasmas.