Enhancement of the thermal barrier depth and two-dimensional potential profiles in GAMMA 10

Ishii, K.; Kawamura, Masaki; Segawa, T.; Katanuma, I.; Mase, A.; Nakashima, Y.; Miyoshi, S.

doi:10.1088/0029-5515/30/6/007

Cited by 32 publications

(7 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Three sets of gold neutral beam probes (GNBPs) are prepared to measure the electrostatic potentials at the thermal barrier region, the inner mirror throat (IMT) of the plug/barrier cell and the solenoid region (z = 1.18 m) of the central cell, respectively [6,7]. A charge-exchange neutral-particle analyzer (CXNPA), which is located near the IMT of the plug/barrier cell, measures the ions bounced at the IMT region and the plug-potential region by selecting the pitch angles of the bounced ions.…”

Section: Tandem Mirror Configurationmentioning

confidence: 99%

Transport of the ion bounced by the plug potential caused by radial electric field in the tandem mirror

et al. 2005

Self Cite

View full text Add to dashboard Cite

In the tandem mirror, plug potentials are created in the plug/barrier cells by microwave injection, and also anchor cells with a minimum B magnetic field configuration are installed in order to reduce the MHD instability. Existence of the ion bounced by the plug potential (PP-bounced ion) is essential for the ion confinement in the tandem mirror. We study the transport of the PP-bounced ion on the assumption that the cross-sectional shape of the magnetic flux tube is slightly different from the cross-sectional shape of the equi-potential surface at the mirror throats of the anchor cell as a small deviation from the equilibrium state. The radial-potential profile of the core plasma is adjusted by controlling the electrostatic potentials of the coaxially separated end plates. We find that the spread type of radial-potential profile is effective for the confinement of the plug-potentialbounced ion.

show abstract

Section: Tandem Mirror Configurationmentioning

confidence: 99%

Transport of the ion bounced by the plug potential caused by radial electric field in the tandem mirror

et al. 2005

Self Cite

View full text Add to dashboard Cite

show abstract

“…Three sets of gold neutral beam probes (GNBPs) were installed at the solenoid region of the central cell and the thermal barrier region of the plug/barrier cell and in the neighborhood of the IMT of the plug/barrier cell, respectively [11,12]. A revised method was adopted for the IMT region, because the magnetic field was very strong and the accessibility was a significant problem [13,14].…”

Section: Gold Neutral Beam Probe System (Gnbp)mentioning

confidence: 99%

Ion Transport in Real and Velocity Space and Confinement in the GAMMA 10 Tandem Mirror.

Ishii

Itakura

Ichimura

et al. 2002

J. Plasma Fusion Res.

View full text Add to dashboard Cite

Loss regions in the plasma particles' velocity space are decreased by the electrostatic potentials created on both sides of the plasma, which results in the improvement of the axial confinement in the tandem mirror. We found experimentally that the ion loss region was in contact mainly with both a plug potential bounce region and the outer mirror throat bounce region in which ions were bounced near the outer mirror throat of the plug/barrier cell. These bounce ions play an important role in tandem mirror confinement. The outer mirror throat bounce region is caused by the relatively high potential in the neighborhood of the outer mirror throat. The core plasma's radial potential profile was controlled by changing the potential of coaxially separated end plates, and it was found that control of the radial potential profile was useful for retardation of the radial loss of the bounce ions. We observed a hump structure on the energy distribution function of the end-loss ions, and found that the enhancement of the end-loss ions was caused by ion flow from the trapped region to the loss region due to Alfvén Ion Cyclotron (AIC) fluctuations. Although the ion diffusion due to the fluctuations enhances the axial ion loss, the axial loss can be reduced by creation of a higher confining potential.

show abstract

“…The potential at the central cell, $ c , and that at the barrier midplane, $ B , are measured with gold neutral beam probes [19], and that at the plug, $ P , is determined by ion energy analysis using multigridded type end loss analysers (ELAs). The radial profile of the potential is measured with the barrier beam probe by sweeping probing beams with different energies, thus covering most of the plasma cross-section within the limiter diameter of 36 cm.…”

Section: Experimental Apparatusmentioning

confidence: 99%

Control of the radial electric field and of turbulent fluctuations in a tandem mirror plasma

et al. 1991

Self Cite

View full text Add to dashboard Cite

The characteristics of low frequency waves in the presence of E x B rotation of a tandem mirror plasma are investigated using the Fraunhofer diffraction method. The observed dispersion relations are in good agreement with those of drift waves including a Doppler shift due to the E x B rotation velocity. The effect of the radial electric field on the drift waves is studied quantitatively by applying a bias voltage to the end plates of the tandem mirror. The fluctuation level is observed to depend on the radial electric field E r . The fluctuation has a maximum value when E r = 0 and decreases with increasing E r , regardless of its sign. The radial confinement time estimated from the particle balance equation decreases as the fluctuation level increases. The dependence of the fluctuation level agrees with that evaluated from the quasi-linear theory of drift wave turbulence.

show abstract

Enhancement of the thermal barrier depth and two-dimensional potential profiles in GAMMA 10

Cited by 32 publications

References 23 publications

Transport of the ion bounced by the plug potential caused by radial electric field in the tandem mirror

Transport of the ion bounced by the plug potential caused by radial electric field in the tandem mirror

Ion Transport in Real and Velocity Space and Confinement in the GAMMA 10 Tandem Mirror.

Control of the radial electric field and of turbulent fluctuations in a tandem mirror plasma

Contact Info

Product

Resources

About