Electron cyclotron resonance as a plasma diagnostic technique in open traps

The electron cyclotron frequency harmonics resonance in a magnetic field, the value of which has an extremum is considered in the study. The calculation of electromagnetic waves absorption coefficients, at electron cyclotron resonance with allowance for various widening mechanisms for the second and higher harmonics, the previously obtained results for the first harmonic are analized. It is shown that the resonance wave absorption near by magnetic field extrema is determined by the nature of absorption line widening while the absorption coefficient being sufficiently remote from extrema is independent of the widening mechanism and may be expressed by an analytical expression. A possibility of using the results obtained for local measurements of plasma density electron distribuin function and magnetic field value in adiabatic traps is discussed