Ion energy balance in T-10

Berezovskij, E.L.; Dnestrovskij, Yu. N.; Efremov, S.L.; Zaveryaev, V.S.; Medvedev, A. A.; Popovichev, S.; Смирнов, А. П.; Tarasyan, K.N.

doi:10.1088/0029-5515/27/12/004

Cited by 11 publications

(6 citation statements)

References 8 publications

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“…Measurements of the time evolution of the 15 MeV proton emission indicated that 0.8 MeV 3 He ions [5] and fast wave heated 3 He minority ions [6] slowed down at roughly the expected rate. On T-10, the time evolution and magnitude of the drop in ion temperature during electron cyclotron heating was consistent with the expected reduction in power flow from the electrons [7]. Although each of these experiments was consistent with classical theory, their accuracy was such that deviations as large as 50%, or more, from theory may have escaped detection.…”

Section: Comparison Of Experimental and Theoretical Fast Ion Slowing-supporting

confidence: 65%

Comparison of experimental and theoretical fast ion slowing-down times in DIII-D

1988

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ABSTRACT. Short deuterium beam pulses are injected into the D III-D tokamak to study the variation of beam slowingdown time with temperature and density. The slowing-down time is inferred from the rate of decay of the d (d,n) 3 He neutron emission. To within ~30%, the results are consistent with Sivukhin's classical theory. The short beam pulses,are also useful for measurements of the central deuterium density.Analysis of tokamak plasmas routinely assumes classical Coulomb coupling between different plasma species. For example, the conclusion that ion thermal conduction is anomalous in beam heated tokamaks [1] hinges on the assumption that the beam power is deposited in the ion channel classically. Only a few experiments have tested the assumption of classical coupling between species. Beam ion spectra measured by charge exchange agreed with spectra computed from classical theory [2,3], although discrepancies of a factor of two were observed in the fits. A higher impurity temperature than hydrogen temperature in low density, * Permanent address: University of California, Irvine, CA 92717, USA.beam heated PLT plasmas was explained by using classical coupling arguments [4]. Measurements of the time evolution of the 15 MeV proton emission indicated that 0.8 MeV 3 He ions [5] and fast wave heated 3 He minority ions [6] slowed down at roughly the expected rate. On T-10, the time evolution and magnitude of the drop in ion temperature during electron cyclotron heating was consistent with the expected reduction in power flow from the electrons [7]. Although each of these experiments was consistent with classical theory, their accuracy was such that deviations as large as 50%, or more, from theory may have escaped detection.Perhaps the best quantitative check of beam energy loss is from studies of the rate of decay of the neutron emission following deuterium beam injection [8,9]. This emission comes from the d (d,n) 3 He reaction between the fast ions and the plasma deuterons. Since the neutron measurement is volume averaged, ±10% uncertainties in the profiles of electron temperature and density have a relatively small effect on the expected rate of decay; hence, the interpretation of the measurements is straightforward. The major weakness of the previous studies [8,9] is that the decay in neutron emission was measured immediately after beam injection, when the classical slowing-down time T S [10] was rapidly changing due to changes in T e and n e . In a preliminary study, Kim et al. attempted to improve the accuracy of the neutron technique by injecting short beam pulses into the D-III tokamak [11].In our experiment, we have studied the deceleration of beam ions by measuring the decay in neutron 1897LETTERS emission following the injection of ~2 ms pulses of deuterium beams into steady state deuterium plasmas in the D III-D tokamak. The total energy injected during the beam pulse was only ~3 % of the plasma stored energy, and, hence, density and temperature of the discharge were not perturbed (T e changed by <5%), ...

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Section: Comparison Of Experimental and Theoretical Fast Ion Slowing-supporting

confidence: 65%

Comparison of experimental and theoretical fast ion slowing-down times in DIII-D

1988

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“…A previous transport analysis of neutral beam heated plasma discharges in the Dili tokamak [1] showed that the ion thermal diffusion coefficient Xi not only was non-neoclassical in magnitude but also exhibited a different radial dependence. In the T-10 tokamak [2], Xi f°r various Ohmic and RF heated plasmas was found to be 1.5 to 4 times the neoclassical value. Ion transport was also found to be anomalous in beam heated ASDEX [3] discharges.…”

Section: Introductionmentioning

confidence: 89%

Ion thermal diffusion in the Texas experimental tokamak

Ouroua¹,

Wootton²,

Bravenec³

et al. 1990

Nucl. Fusion

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Profiles of the ion thermal diffusion coefficient χi have been determined experimentally for several TEXT plasma discharges. In the confinement region, the inferred values of χi are larger than the values predicted by neoclassical theory by a factor of two to six. No evidence of a reduction of thermal losses through the ion channel is found after injection of hydrogen pellets. The inferred electron thermal conductivities are larger than the ion thermal conductivities by an average factor of three. The anomaly in χi is compared with transport coefficients predicted by different models that describe the ηi instability.

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“…The electron temperature profiles Tg Xp (r) were measured by the 2nd harmonic of electron cyclotron emission (ECE), soft X-ray (SXR) spectra and Thomson scattering of laser beams. The ion temperature profiles Tj exp (r) were determined by charge exchange spectra, Doppler broadening of visible carbon lines (on the plasma edge) and absolute measurements of neutron flux (in the plasma core) [19].…”

Section: Simulation Of Ecrh Experiments On T-10mentioning

confidence: 99%

Transport model of canonical profiles for electron and ion temperatures in tokamaks

Dnestrovskij¹,

Berezovskij²,

Лысенко³

et al. 1991

Nucl. Fusion

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A set of transport equations using canonical ion and electron temperature profiles is proposed. Simulations of electron cyclotron resonance heating on T-10 and of the L-mode in TFTR, JET and ASDEX have been performed. From an analysis of the results of the calculations it is possible to construct universal expressions for heat fluxes without free parameters. On the basis of the developed model, several predictions are made for the International Thermonuclear Experimental Reactor (ITER).

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Ion energy balance in T-10

Cited by 11 publications

References 8 publications

Comparison of experimental and theoretical fast ion slowing-down times in DIII-D

Comparison of experimental and theoretical fast ion slowing-down times in DIII-D

Ion thermal diffusion in the Texas experimental tokamak

Transport model of canonical profiles for electron and ion temperatures in tokamaks

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