Controlling the resistive wall instability in the Fermilab Main Ring

The Fermilab Main Ring has a strong transverse instability identified as a resistive wall. Previous methods of dealing with this problem have primarily been to find settings of tune, chromaticity, and octupole that result in stable operation. Controlling this instability in this manner has had limited success and reduces beam lifetime. A new damper system has been installed in the Main Ring to control this instability. This damper effectively provides a negative impedance to the accelerator to cancel the effects of the resistive wall. With this damper in operation we have been able to adjust the tune, chromaticity, and octupole settings to improve beam efficiency without becoming unstable due to the resistive wall of the accelerator.