In some embodiments, a nuclear magnetic resonance (NMR) method comprises
generating an indicator of an anticipated time-averaged power for a
radio-frequency (RF) pulse set, and anticipatively adjusting a cooling
supplied by a cryogenic cooling fluid to an RF coil according to the
indicator of the anticipated time-averaged power. The cryogenic cooling
adjustment may be performed using a cryogenic fluid heater and/or a mass
flow controller disposed in the cryogenic fluid path. The time difference
between the start of the cooling adjustment and the start of the RF pulse
set is set to be equal to the difference in timescales between the
cooling effect of the cooling adjustment and the heating effect of the RF
pulse set on the RF coil.