ICRF heating experiments on JIPP T-II

Ichimura, M.; Fujita, J.; Hirokura, S.; Kako, E.; Kawahata, K.; Kawasumi, Y.; Nishizawa, A.; Noda, N.; Ogawa, I.; Ohkubo, Κ.; Sasao, M.; Shinohara, Shunji; Tanahashi, S.; Tetsuka, T.; Toi, K.; Watari, T.; Aoki, Takashi; Hidekuma, S.

doi:10.1088/0029-5515/24/6/003

Cited by 12 publications

(10 citation statements)

References 8 publications

(11 reference statements)

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“…The d(3He, p ) a reaction rate during deuterium minority heating in a 3He majority plasma was also consistent [55]. In J I P P T-11, the hydrogen minority tail temperature measured with passive charge exchange was close to the temperature predicted by a model based upon the Stix formalism [97].…”

Section: Icrf Wavessupporting

confidence: 59%

The behaviour of fast ions in tokamak experiments

1994

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ABSTRACT. Fast ions with energies significantly larger than the bulk ion temperature are used to heat most tokamak plasmas. Fast ion populations created by fusion reactions, by neutral beam injection and by radiofrequency (RF) heating are usually concentrated in the centre of the plasma. The velocity distribution of these fast ion populations is determined primarily by Coulomb scattering; during wave heating, perpendicular acceleration by the RF waves is also important. Transport of fast ions is typically much slower than thermal transport, except during MHD events. Intense fast ion populations drive collective instabilities. Implications for the behaviour of alpha particles in future devices are discussed.

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Section: Icrf Wavessupporting

confidence: 59%

The behaviour of fast ions in tokamak experiments

1994

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“…Therefore, the total absorption is almost independent of the dissipation rate v/w. These features are characteristic of power absorption associated with the spatial resonance surface [13]. From the local approximation, we have W«Im {l/(S*-k 2 c 2 /<o 2 )} (caseof k y -+0), which implies a Lorentz-type profile in the x-direction when the value of P/CO is small.…”

Section: Values Of Kn Defined Bymentioning

confidence: 90%

“…Equations ( 9) and ( 10) are numerically solved with the boundary conditions (11) to (13). (The numerical procedure is briefly described in the Appendix.)…”

Section: Analysis Of Wave Propagation and Absorptionmentioning

confidence: 99%

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Three-dimensional structures of ICRF waves in tokamak plasmas

Itoh¹,

Itoh

Fukuyama

1984

Nucl. Fusion

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The three-dimensional structure of ICRF (Ion Cyclotron Range of Frequency) waves in a tokamak plasma is investigated. In a two-ion-species plasma (majority deuterium and minority hydrogen) with radial density inhomogeneity, the wave equation is solved numerically by employing a cold-plasma approximation. The plasma is immersed in a toroidal magnetic field with a gradient and is surrounded by the vacuum region and the conducting wall. Waves are launched by a Faraday-shielded poloidal-current antenna of finite extent in toroidal and poloidal directions. The wave field and the energy deposition profile are obtained by introducing a simple model for the collision. The wave accessibility condition is examined for plasma parameters and density profiles. In a cold-fluid approximation, two mechanisms of power absorption, i.e. two-ion hybrid resonance and cavity resonance, are found, and the differences between them are studied. The antenna loading impedance is also calculated for each case. High-and low-field-side excitations are compared. Non-plasma losses at the wall are considered in obtaining the coupling efficiency. Good coupling conditions and desirable antenna designs are also discussed. It is found that efficient coupling is expected in a wide range of plasma parameters.

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“…The quenching is usually related to: (i) missing correlations in the wave function, (ii) truncation of model space or (iii) to a very fashionable nowadays renormalization of the GT operator due to the two-body currents [11,12]. Scenarios involving nonnucleonic degrees of freedom like N N → N ∆ excitations are shown to contribute only rather weakly [13].…”

Section: (Eff)mentioning

confidence: 99%

β-decay study within multireference density functional theory and beyond

2016

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Pioneering study of Gamow-Teller (GT) and Fermi matrix elements (MEs) using no-coreconfiguration-interaction formalism rooted in multi-reference density functional theory is presented. After successful test performed for 6 He→ 6 Li β-decay, the model is applied to compute MEs in the sd-and pf -shell T =1/2 mirror nuclei. The calculated GT MEs and the isospin-symmetry-breaking corrections to the Fermi branch are found to be in a very good agreement with shell-model predictions in spite of fundamental differences between these models concerning model space, treatment of correlations or inclusion of a core. This result indirectly supports the two-body current based scenarios behind the quenching of axial-vector coupling constant.PACS numbers: 21.10. Hw, 21.60.Jz, 21.30.Fe, 23.40.Hc, 24.80.+y The atomic nuclei are unique laboratories to study fundamental processes and search for possible signals of new physics beyond the Standard Model in ways that are complementary or even superior to other sciences. This is due to enhanced sensitivity of specific isotopes to fundamental symmetries caused, in particular, by intrinsic-symmetry-related or purely accidental (near-)degeneracies of nuclear states. For example, parity doublets caused by stable octupole deformation increase sensitivity to search for the violation of CP-symmetry which is responsible for matter over anti-matter dominated Universe [1]. Accidental near-degeneracy of 3/2 + and 5/2 + levels in 229 Th, which are separated only by 7.6±0.5 eV, opens up a possibility for high-precision measurement of the temporal variation of fine-structure constant with much higher sensitivity as compared to the atomic transitions [2]. Last but not least, nuclear physics input is critical in an ongoing hunt for a weakly-interacting massive particle (WIMP), a candidate for dark matter, in direct detection experiments measuring the recoil energy deposited when WIMP is scattered off the nucleus, see [3] and refs. quoted therein.Traditionally, the atomic nuclei are used to study the weak interaction. A flagship example is the superallowed I=0 + →I=0 + β-decay among the members of the isobaric triplets T =1. With small, of order of a percent, theoretical corrections accounting for radiative processes and isospin symmetry breaking (ISB), these semileptonic pure Fermi (vector) decays allow to verify the conserved vector current (CVC) hypothesis with a very high precision. In turn, they provide the most precise values of the strength of the weak force, G F , and of the leading element, V ud , of the Cabbibo-Kobayashi-Maskawa (CKM) matrix, see [4] for a recent review.The T =1/2 mirror nuclei offer an alternative way to test the CVC hypothesis [5]. These nuclei decay via the mixed Fermi and Gamow-Teller (GT) transitions. Hence, apart from the radiative and the ISB theoretical corrections, the final values of G F and V ud depend on the ratio of statistical rate functions for the axial-vector and vector interactions, f A /f V , and the ratio of nuclear matrix elements ρ ≈ λM GT /M F where ...

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ICRF heating experiments on JIPP T-II

Cited by 12 publications

References 8 publications

The behaviour of fast ions in tokamak experiments

The behaviour of fast ions in tokamak experiments

Three-dimensional structures of ICRF waves in tokamak plasmas

β-decay study within multireference density functional theory and beyond

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