  Many experiments suggest that the unidentified low temperature phase (LTP) of
alpha-(BEDT-TTF)_2KHg(SCN)_4 is most likely unconventional charge density wave
(UCDW). To further this identification we present our theoretical study of the
threshold electric field of UCDW in a magnetic field. The magnetic
field-temperature phase diagram is very similar to those in a d-wave
superconductor. We find a rather strong field dependence of the threshold
electric field, which should be readily accessible experimentally.
