On the Mechanism of Energetic Electron Losses from the Magnetic Mirror Trap at the ECR Discharge Startup

In this work, we discuss experimental evidence for the existence of an effective mechanism of energetic-electron losses at the initial stage of the discharge during electron cyclotron resonance (of the ECR discharge) when the electron scattering to the loss cone is caused by the development of the electron cyclotron instabilities of a strongly nonequilibrium plasma. The spectral composition of the transient pulses of electromagnetic radiation is studied in a wide frequency range at the initial stage of the ECR discharge, when the hot-particle density exceeds that of cold particles. The observed electromagnetic-radiation bursts and synchronous energetic-electron precipitation from the trap can be related to the development of a cyclotron instability of the fast extraordinary wave in the rarefied plasma.