Ignition Analysis for D Plasma with Non-Maxwellian 3He Minority in Fusion Reactors

Shyshkin, Oleg; Moskvitin, A. O.; Moskvitina, Yuliya K.; Yanagi, N.; Sagara, A.

doi:10.1585/pfr.6.2403064

Cited by 2 publications

(2 citation statements)

References 6 publications

(29 reference statements)

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“…This phenomenon significantly modifies the characteristics of plasma in general that is clearly demonstrated on Tokamak JET [1,2]. At present time the variety of numerical techniques to simulate the transition from Maxwellian to non-Maxwellian distribution is developed [3][4][5]. At the same time in order to get the comprehensive description of plasma dynamics one should take care of plasma particles interaction, i.e.…”

Section: Introductionmentioning

confidence: 99%

Test Particle Simulations for Non-Maxwellian Plasma Transport: Discretized Collisional Operator

Vozniuk¹,

Shyshkin²,

Гірка³

2021

Problems of Atomic Science and Technology

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The plasma observed in modern fusion devices is very often characterized by strongly non Maxwellian distribution function. That is the direct result of inevitable application of plasma heating techniques, such as neutral beam injection (NBI) and ion/electron cyclotron resonance frequency (ICRF/ECRF) heating, which induce the non Maxwellian fast ions. Another cause of transfer from Maxwellian to non Maxwellian is the reconnection of magnetic field lines followed by formation of magnetic resonant structures like magnetic islands and stochastic layers. One of the basic approaches used to simulate fusion plasma is test particle approach based on a solution of the equations of test particle motion. To make this approach more comprehensive one should take care of plasma particle interactions, i.e. Coulomb collisions in non Maxwellian environment. In present paper the expressions for the discretized collision operator of a general Monte Carlo equivalent form in terms of expectation values and standard deviation for an arbitrary non Maxwellian bulk distribution function are derived. The modification of transport coefficients of impurity ions caused by the transition from the background Maxwellian to non Maxwellian plasma is studied by means of this discretized collision operator. On this purpose, the set of monoenergetic neon test impurities is followed in a toroidal plasma consisting of bulk deuterons and electrons. The non Maxwellian distribution of the bulk is obtained by adding a fraction of energetic particles of the same species. It is demonstrated that a change of collision frequencies of impurities takes place in presence of this energetic fraction leading to a change of impurity neoclassical transport regime.

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Section: Introductionmentioning

confidence: 99%

Test Particle Simulations for Non-Maxwellian Plasma Transport: Discretized Collisional Operator

Vozniuk¹,

Shyshkin²,

Гірка³

2021

Problems of Atomic Science and Technology

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show abstract

“…In our further analysis, we also need to incorporate more precise analysis, such as the test particle calculation. 3 On the other hand, we consider that the application of ICRF heating could be used for producing tritium in D-D operations in order to start up a D-T reactor without an external supply of tritium loading. …”

mentioning

confidence: 99%

Feasibility of Reduced Tritium Circulation in the Heliotron Reactor by Enhancing Fusion Reactivity Using ICRF

Yanagi

Shyshkin

Goto

et al. 2011

Plasma and Fusion Research

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Handling of tritium is one of the most important technological issues for realizing fusion power plants. Since the burning ratio of the presently designed deuterium-tritium (D-T) fusion reactors remains in a couple of percentage level, a large amount of tritium should be recovered from the vacuum vessel and constantly circulated in the reactor system. A big concern is the permeation and retention of tritium within the vacuum vessel and circulation plumbing. Moreover, unless the recovery rate is close to 1, it would be very difficult to obtain the sufficient tritium breeding ratio (TBR). In this respect, it would be useful if the D-T reactivity is enhanced by applying high-power Ion Cyclotron Range of Frequency (ICRF) waves for producing high-energy tails accelerated by wave-particle energy transfers. 1 We examine an enhancement of fusion reactivity in the power balance equation by including high-energy components of tritons. For this purpose, we crudely assume that the high-energy component can be expressed by a Maxwellian distribution function having an effective temperature. 2 As shown in Fig. 1, if the high-energy temperature is 10 times the temperature of bulk deuterons, the fusion reactivity is found to be ~10 times the value without having a high-energy component, in the energy range of deuterons lower than ~10 keV. Using the enhanced fusion reactivity in Fig. 1, we then solve the power balance for the D-T fusion reaction, and the result is shown in Fig. 2 for the tritium fractions of 1, 2, 3, 5 and 10%. 2 Here the Q-value is assumed to be 10. We observe that there is a significant reduction for the required density, energy confinement time and bulk temperature compared to the standard case for the 50%-50% D-T ratio with Q = ∞ (self-ignition).In order to examine the feasibility of having the generation high-energy tritons using minority ICRF heating, we examine the ξ-parameter derived by T.H. Stix. We found that it reaches up to ~9 under the condition of electron density: 0.8×10 20 m -3 , tritium ratio 5%, energy confinement time: 2.4 s, electron temperature: 6 keV, and the volume averaged ICRF power: 0.2 MW/m 3 . This value of the ξ-parameter gives the effective temperature of tritium ~10 times the bulk deuteron temperature. However, we also found that the Q-value reaches only 5 in this case. In another condition, we find that Q reaches up to 10 but this is still not sufficient. These results suggest that we need to consider some more improvement to make this scenario attractive and practical. In our further analysis, we also need to incorporate more precise analysis, such as the test particle calculation. 3 On the other hand, we consider that the application of ICRF heating could be used for producing tritium in D-D operations in order to start up a D-T reactor without an external supply of tritium loading.

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Ignition Analysis for D Plasma with Non-Maxwellian 3He Minority in Fusion Reactors

Cited by 2 publications

References 6 publications

Test Particle Simulations for Non-Maxwellian Plasma Transport: Discretized Collisional Operator

Test Particle Simulations for Non-Maxwellian Plasma Transport: Discretized Collisional Operator

Feasibility of Reduced Tritium Circulation in the Heliotron Reactor by Enhancing Fusion Reactivity Using ICRF

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