[en] Ion cyclotron heating is efficiently used to produce and to heat plasma in magnetic mirrors. In plasma with rather low (less than 10¹⁸ m^-3) density the fast Alfven normal modes are generated both radially and longitudinally and plasma density affects essentially excitation of these modes. To heat plasma one uses efficiently the low Alfven waves. During the experiments one obtained ionic temperature exceeding 10 keV and it is confirmed via observation of fusion neutrons. Excitation of the Alfven normal modes is investigated in detail in the GAMMA 10 ambipolar trap

[en] Waves in the ion cyclotron range of frequency are efficiently used to produce and heat magnetic mirror plasmas. In relatively low-density (lower than 10¹⁸ m^-3) plasmas, the fast Alfven eigenmodes are formed in radial and axial directions and the excitation of these modes is strongly affected by the density. The slow Alfven waves are also effectively used for plasma heating. The ion temperature above 10 keV is achieved, which is confirmed by the detection of fusion neutrons. The excitation of Alfven eigenmodes is studied in the GAMMA 10 tandem mirror

[en] In the GAMMA 10 tandem mirror, fAlfven ion cyclotron modes are spontaneously excited due to the strong temperature anisotropy. The plasma parameters needed for the excitation are explained by the theoretical prediction with the effective mirror ratio. It is suggested that the power of ICRF waves applied externally branches off spontaneously excited Alfven eigenmodes directly

[en] After the attainment of the density doubling due to the potential confinement, GAMMA 10 experiments have been directed to obtain a high-density plasma with potential confinement and also to study the dependence of the confining potential and confinement time on the plasma density. These problems are important to understand the physics of potential formation in tandem mirrors and also for the development of a tandem mirror reactor. GAMMA 10 experiments have advanced greatly after the Sorrento IAEA Conference, where high-density plasma production by using an ICRF heating at a higher harmonic frequency was reported. Recently, a high-density plasma was attained and the reproducibility of high-density plasma production was much improved by adjusting the spacing of the conducting plates installed in the anchor transition regions. In this paper, we report the production of a high-density plasma and the dependence of the confining potential and confinement time on the density up to a density of 4 x 10¹² cm^-3

[en] GAMMA 10 experiments have advanced in high density experiments after the last IAEA fusion energy conference in 2000 where we reported the production of the high density plasma through use of ion cyclotron range of frequency heating at a high harmonic frequency and neutral beam injection in the anchor cells. However, the diamagnetic signal of the plasma decreased when electron cyclotron resonance heating was applied for the potential formation. Recently a high density plasma has been obtained without degradation of the diamagnetic signal and with much improved reproducibility than before. The high density plasma was attained through adjustment of the spacing of the conducting plates installed in the anchor transition regions. The potential confinement of the plasma has been extensively studied. Dependences of the ion confinement time, ion-energy confinement time and plasma confining potential on plasma density were obtained for the first time in the high density region up to a density of 4x10¹⁸ m^-3. (author)