Kakuyūgō kenkyū

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The excitation of ion cyclotron waves and associated heating of ions by an electron beam which is transversely modulated near ion cyclotron frequency are studied experimentally. The wave length, the intensity of the excited waves and the ion temperature are measured in detail. The wave length is found to be proportional to the beam velocity and to the reciprocal of the magnetic field. The ion temperature in the direction perpendicular to the magnetic field is enhanced than that of the axial direction within a mirror machine. When the modulation frequency almost coincides with the ion cyclotron frequency, we observe the remarkable heating of ions. At a magnetic beach, the excited waves steeply damp and at the same time the ion temperature has a sharp peak. In the case of hydrogen plasmas, two peaks of ion temperature due to resonance of H⁺-and H⁺₂-ions are observed.
The ion heating seems to be due to damping of ion cyclotron waves excited by a coupling with slow cyclotron waves of the electron beam.

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