Sub-Thz Wave Generation by Plasma under High-Current Relativistic Electron Beam Impact in the GOL-PET Experiment
A.V. Arzhannikov1,2, A.V. Burdakov1, V.S. Burmasov1,2, L.N. Vyacheslavov1,2, I.A. Ivanov1,2, A.A. Kasatov1, S.A. Kuznetsov2, M.A. Makarov1, K.I. Mekler1, S.V. Polosatkin1,2, V.V. Postupaev1,2, S.L. Sinitsky1,2, V.F. Sklyarov1,2
1Budker Institute of Nuclear Physics, Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Russia
In the paper, last experiment’s results on sub-THz wave emission from the area of relativistic electron beam-plasma interaction in the GOL-PET device are described . A plasma column with the diameter of 6 cm, length of 2.5 m and its density (0.2-2) x1015 cm-3 is confined by multiple-mirror magnetic field with mean value of 4 T. The electron beam (REB) injected into the column, has the following parameters: energy Eb ~ 0.8 MeV, current Ib ~ 30 kA, current density Jb ~ 2 kA/cm2 in the mean magnetic field. Previous studies  have shown that the beam is pumping the plasma electron oscillations in a vicinity of the upper hybrid wave branch. These plasma oscillations can be converted in electromagnetic waves on regular or artificial plasma density gradients (the plasma radiation with the upper hybrid frequency). The electromagnetic waves with the double upper hybrid frequency are also generated in the beam-plasma system due to coalescence of the plasma oscillations in case of high level of the oscillation energy density.
The described experiments are devoted to measure the spectral properties of the generated radiation and the directions of the sub-THz plasma emission in depending on plasma and beam parameters. As results of these experiments, the wave emission with the specific power concentrated in the direction along the axis of the plasma column, in the frequency interval 0.25-0.5 THz has been obtained at the plasma density about of 1015 cm-3.
This research was financially supported by RSCF under Project No. #14-12-00610 for the investigation of sub-terahertz emission from plasmas. The upgrade of the radiometric system was funded by the Ministry of Education and Science of RF under the State Assignment Contract No. #3002.
1. A. V. Arzhannikov et al., Dynamics and Spectral Composition of Subterahertz Emission From Plasma Column Due to Two-Stream Instability of Strong Relativistic Electron Beam // IEEE Trans. THz Sci. Technol., V6, N2, 245 (2016), doi: 10.1109/TTHZ.2016.2525783.
2. A.V. Arzhannikov et al., Observation of spectral composition and polarization of sub-terahertz emission from dense plasma during relativistic electron beam-plasma interaction// Phys. Plasmas, Vol. 21, No. 8, 2014, Art. ID 082106.