Electron energy increase of an REB-ring by major radius compression

Measurement of X-ray bremsstrahlung emitted from REB rings formed in SPAC-Vl toroidal device elucidated that major radius compression of the ring raises energies of the ring electrons. At the compression ratio of 2.0, the ring current rose from 24 kA to 50 kA. The highest energy of electrons that was estimated by hard X-ray spectrum measurement increased from ∼1 MeV to ∼2 MeV. The energy distribution of REB was broadly spread. During the compression, the current of ring I R and the major radius R are governed by the relation I R · R =const. Some discussions on this relation are given in which energy spread of the beam electrons and the change in the magnetic flux enclosed by the ring are taken into consideration.