Effect of nuclear elastic scattering on ion heating characteristics in deuterium-tritium thermonuclear plasmas

Abstract

An effect of nuclear elastic scattering ͑NES͒ on the energy transfer to plasma ions and electrons during ͑a͒ neutral beam injection ͑NBI͒ and ͑b͒ ␣-particle heating operations is examined on the basis of the Boltzmann-Fokker-Planck ͑BFP͒ equation for a beam ion and an ␣-particle in deuterium-tritium thermonuclear plasmas. The BFP calculations show that the enhancement in the fraction of the NBI heating power deposited to ions due to NES becomes appreciable when the beam energy is larger than 1 MeV. How the NES effect is influenced by the plasma condition is discussed.

Knock-on Tail Formation Due to Nuclear Elastic Scattering and Its Observation Method Using <i>γ</i>-Ray-Generating ⁶Li+d Reaction in Tokamak Deuterium Plasmas

“…As was discussed in Ref. [5], for the present study the γ is not an influential parameter. Considering both energy loss mechanisms due to thermal conduction and particles transport loss from the plasma, the confinement time due to conduction loss τ C is determined for each ion species using the global energy confinement time τ E so that the following relation is satisfied for each species,…”

“…In such a case, NES effects on slowing down of energetic ions would not be negligible compared with those due to Coulomb collisions. We have evaluated the NES effects on burning plasma properties for several situations that energetic ions exist [5][6][7], on the basis of the Boltzmann-Fokker-Planck (BFP) analysis model [5,[8][9][10]. Many calculations have predicted that NES accelerates slowing-down process of fast ions and enhances the fractional energy deposition from fast to bulk ions [11][12][13].…”

A Method of Knock-on Tail Observation Accounting Temperature Fluctuation Using ⁶Li+T/D+T Reaction in Deuterium Plasma

“…Here, the bulk temperature is fixed to 2 keV to investigate the effect of the knock-on tail formation. The deuteron distribution function when T bulk = 2 keV, T tail = 90 keV, and α = 0.0002 is chosen based on the results of the BFP simulation [16] when a proton beam [power (P NBI = 33 MW) and energy (E NBI = 1 MeV)] is injected into the deuterium plasma. The source term in Eq.…”

Alpha Particle Slowing-Down Characteristics and the Effect on MHD Instability Excitation at High-Density Operation Points in FFHRs

“…As discussed in Ref. 8, in typical plasma conditions, γ would not be a significant parameter if we choose sufficiently large values, e.g., γ ≥ 4. Considering the energy loss mechanisms resulting from both thermal conduction and particles transport loss from plasma, the global energy confinement time is defined as…”

“…The second term on the right-hand side of Eq. (1) accounts for nuclear plus interference (NI) scattering [7] of alpha particles by background ions n [8]. We consider NI scattering between 1) alpha particles and deuterons, 2) alpha particles and tritons.…”