Loss of 3.52-MeV alpha particles in a tokamak reactor

Ohnishi, Masami; Tokunaga, Hisahiro; Wakabayashi, Jiro

doi:10.1088/0029-5515/16/4/017

Cited by 14 publications

(18 citation statements)

References 6 publications

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“…Though the containment properties of the alpha particles strongly depend on the radial profile of the toroidal current density [1,3,5], we shall, for simplicity, assume a flat current distribution. On these assumptions, the magnetic field is given by (Fig.…”

Section: Analytical Model and Assumptionsmentioning

confidence: 99%

“…Stringer [2] obtained an analytic expression for the alpha-particle source distribution considering the drift orbit effects. Ohnishi et al [3] studied the sensitivity of alpha-particle loss to some tokamak reactor parameters by using numerical integrations of the drift orbits. Kolesnichenko et al [4] studied the confinement of alpha particles, together with the streaming of these particles towards the chamber walls in an axisymmetric tokamak.…”

Section: Introductionmentioning

confidence: 99%

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Loss of alpha particles during slowing-down in an axisymmetric tokamak reactor

Ohnishi

Wakabayashi

1978

Nucl. Fusion

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The containment properties of alpha particles during the slowing-down process in an axisymmetric tokamak reactor are studied by using Monte-Carlo calculations, in which the pitch-anglescattering effects are included. The loss of alpha particles during slowing-down is found to be safely negligible in a pure DT plasma, but increases proportionally to the effective charge number of the plasma and cannot be ignored in a highly contaminated plasma (Z e ff > 4), compared with the loss of 3.5-MeV particles.

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Section: Analytical Model and Assumptionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Loss of alpha particles during slowing-down in an axisymmetric tokamak reactor

Ohnishi

Wakabayashi

1978

Nucl. Fusion

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“…Generally, fast ions are well confined in axi-symmetric tokamaks and are lost to the first wall mainly due to the non-axisymmetric component of the magnetic field [20,21].…”

Section: Review Of the Basic Effects Of The Radial Electric Field On mentioning

confidence: 99%

Effects of the radial electric field on the confinement of fast ions in ITER

Tani¹,

Honda

Oikawa

et al. 2015

Nucl. Fusion

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The effects of a radial electric field (EF) on the losses of alpha particles and NBI fast ions in typical ITER operation scenarios for both error fields due to test blanket modules (TBMs) and toroidal field (TF) ripple were evaluated using an iterative method to execute an orbit-following Monte-Carlo code and a one-dimensional transport code. The EF effect on the loss of fast ions strongly depends on the operation scenario as well as on the error field. The electric field is very significant in the loss of fast ions in a 9MA ITER operation scenario with a higher safety factor and in the error field associated with TBMs. The EF effect in the error field of TF-ripple is very small in any operation scenario. The electric field is much more significant for the loss of NBI fast ions than for that of alpha particles. The radial electric field changes the toroidal precession of fast ions and consequently alter their condition of resonance with the error field, which may account for the EF effect on the loss of fast ions in ITER with TBMs.

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“…This quantity is not difficult to evaluate numerically, and has been done so by several authors (e.g., Refs. (8), (58) and (59)). As we 28 will show, this tends to reduce the discrepancy between "in situ" and the other techniques by accounting for suprathermal product losses.…”

Section: Radial Heating Profilementioning

confidence: 99%

Effects of suprathermal fusion particles in tokamak plasmas

Pétrie¹

1978

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Several crucial properties of suprathermal (>500 keV) fusion-products are explored, both in their initial phase and during their slowingdown period. A guiding center drift theory, which predicts the effect of energy loss. on. the motion of these suprathermals, is derived for a low-B, symmetric (non-ripple) tokamak. Velocity-space scattering is ignored. Among the important implications of this theory are: (1) the net inward drift of fusion particles during their slow-down phase, and (2) the importance of the plasma density and temperature in determining ·this drift.The effect the inward drifting has on the spatial profile for the suprathermals approaching thermal energies, on the energy distribution, and on the plasma heating profile is demonstrated for five reactor cases, ranging from near-term low-current devices to conceptual power reactors. It is found that "in situ" energy deposition is a reasonable assumption for the higher current machines, like UWMAK I, differing in the plasma heating evaluation by only a few percent from our more exact treatment (SYMALF) over most of the plasma. However, for lower current tokamaks, the discrepancies between "in situ" and SYMALF can become quite sizeable (%25%)..It is also shown that, due to the slowing-down drifts, the fusion-product energy distribution near the plasma edge can have a positive slope with increasing energy, suggesting a possible driving mechanism for microinstabilities.In the case of magnetic ripple, a probabilistic density function is employed to determine drift losses associated with ripple trapped, .3.52-MeV alpha particles. When used to determine 3.52-MeV alpha particle wall-loadings, code RIPALF, which is based on this probability function, predicts the position of local "hot spots" along the first wall.

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Loss of 3.52-MeV alpha particles in a tokamak reactor

Cited by 14 publications

References 6 publications

Loss of alpha particles during slowing-down in an axisymmetric tokamak reactor

Loss of alpha particles during slowing-down in an axisymmetric tokamak reactor

Effects of the radial electric field on the confinement of fast ions in ITER

Effects of suprathermal fusion particles in tokamak plasmas

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