  We report results of the experimental test of the High Temperature
Superconductor based fast cycling prototype accelerator magnet capable to
operate up to about 300 Tesla per second field ramping rate with some 0.5 T
field in the magnet gap. The measured upper limit for the cryogenic cooling
power required to support magnet conductor operation at high ramping rates
indicates great potential for such types of magnets in rapid cycling
synchrotrons for neutrino research or muon acceleration. The test magnet
design, construction, and supporting cryogenic and power systems are briefly
described. The magnet power test results are discussed in terms of a possible
upgrade of this magnet design to 2 T field, a maximum feasible with superferric
magnet.
