Measurement of the electron Bernstein wave emission with one of the power transmission lines for ECH in LHD

摘要

Possibility of the measurement of radiated waves derived from the thermally emitted electron Bernstein wave (EBW) has been numerically investigated on the assumption of a super dens core plasma generated in the large helical device (LHD). The EBW that is thermally emitted in the electron cyclotron resonance (ECR) layer may couple with the electromagnetic wave and be emitted to the vacuum via the EBW-extraordinary-ordinary (B-X-O) mode conversion process. We consider using one of the transmission lines for electron cyclotron heating (ECH) in the LHD as a receiving system of the emission. It has been derived that the measurement of the waves in the fundamental cyclotron frequency range does not provide information in the core region of the plasma since the emission region is near the their upper hybrid resonance layer outside the last closed flux surface (LCFS). On the other hand, measurement of the waves in the second harmonic frequency range provides information of the core region. It means successfully measurement of waves in the second harmonic frequency range emitted from extremely high dens core plasma indicates the possibility of the second harmonic ECH by the EBW in the core region with the same aiming and polarization.