Upshifted electron cyclotron emission

The possibility of inferring the high energy part of the electron distribution function by means of its electron cyclotron emission is investigated. It is shown, with different set-ups, that the emission leaving the plasma perpendicular to the magnetic field cannot achieve this goal. A new configuration viewing the plasma from the low field side, oblique respect to the magnetic field -upshifted emission — is presented and its useful properties for localizing the electrons, responsible for the emission, in real and momentum space discussed.