This disclosure relates generally to methods and devices for modifying biological tissue. In one embodiment, a device is provided suitable for applying RF energy to a treatment site in the presence of a supplemental magnetic field. The device comprises one or more electrodes electrically coupled to an RF generator, and a means for supplying a supplemental magnetic field. In another embodiment, a device is provided suitable for inducing an electrical current in a tissue. The device comprises a means for creating a magnetic field and a passive element adapted for reducing the amount of electrical current at the surface of the tissue. Also provided are methods of use of such devices. The methods and devices disclosed herein find utility, for example, in the field of medicine and cosmetology.