Heating mechanisms in radio-frequency-driven ultracold plasmas

Several mechanisms by which an external electromagnetic field influences the temperature of a plasma are studied analytically and specialized to the system of an ultracold plasma (UCP) driven by a uniform radio-frequency (rf) field. Heating through collisional absorption is reviewed and applied to UCPs. Furthermore, it is shown that the rf field modifies the three-body recombination process by ionizing electrons from intermediate high-lying Rydberg states and upshifting the continuum threshold, resulting in a suppression of three-body recombination. Heating through collisionless absorption associated with the finite plasma size is calculated in detail, revealing a temperature threshold below which collisionless absorption is ineffective.