Simulating fusion alpha heating in a stellarator reactor

2021 ◽  
Author(s):  
Samuel A Lazerson ◽  
Alexandra LeViness ◽  
Jorrit Lion
Keyword(s):  
Energetic Particle ◽  
Fusion Reactor ◽  
Plasma Heating ◽  
Alpha Particles ◽  
Slowing Down ◽  
Scaled Energy ◽  
Heating Profiles ◽  
Fusion Products ◽  
Mirror Configuration ◽  
Density Plasma

Abstract Gyrocenter following simulations of fusion born alpha particles in a stellarator reactor are preformed using the BEAMS3D code. The Wendelstein 7-X high mirror configuration is scaled in geometry and magnetic field to reactor relevant parameters. A 2×1020 m−3 density plasma with 20 keV core temperatures is assumed and fusion birth rates calculated for various fusion products assuming a 50/50 deuterium-tritium mixture. It is found that energetic He4 ions comprise the vast majority of the energetic particle inventory. Slowing down simulations of the He4 population suggest plasma heating consistent with scaled energy confinement times for a stellarator reactor. Losses for this configuration appear large suggesting optimization beyond the scope of the W7-X device is key to a future fusion reactor. These first simulations are designed to demonstrate the capability of the BEAMS3D code to provide fusion alpha birth and heating profiles for stellarator reactor designs.

Ion cyclotron emission due to fast Alfvén-wave radiative instabilities in tokamaks induced by newly born fusion products

1997 ◽  
Vol 58 (2) ◽  
pp. 287-313 ◽  
Author(s):  
V. ARUNASALAM
Keyword(s):  
Distribution Functions ◽  
Alpha Particles ◽  
Alfven Wave ◽  
Fusion Product ◽  
Deuterium Plasma ◽  
Thermalization Time ◽  
Slowing Down ◽  
Velocity Distribution Functions ◽  
Product Species ◽  
Fusion Products

The velocity distribution functions of newly born (t=0) charged fusion products (protons in DD and alpha particles in DT plasmas) of tokamak discharges can be approximated by a monoenergetic ring distribution with a finite v∥ such that v⊥≈v∥ ≈Vj, where ½MjV2j =Ej, the directed birth energy of the charged fusion-product species j of mass Mj. As the time t progresses, these distribution functions will evolve into a Gaussian in velocity (i.e. a drifting Maxwellian type), with thermal spreads given by the perpendicular and parallel temperatures T⊥j(t) =T∥j(t), with Tj(t) increasing as t increases and finally reaching an isotropic saturation value offormula hereHere Td is the temperature of the background deuterium plasma ions, M is the mass of a triton or a neutron for j=protons and alpha particles respectively, and τj≈¼τsj is the thermalization time of the fusion product species j in the background deuterium plasma, with τsj the slowing-down time. For times t of the order of τj, the distributions can be approximated by a Gaussian in the total energy (i.e. a Brysk type). Then, for times t[ges ]τsj, the velocity distributions of the fusion products will relax towards their appropriate slowing-down distributions. Here we shall examine the radiative stability of all these (i.e. a monoenergetic ring, a Gaussian in velocity, a Gaussian in energy, and the slowing-down) distributions.

Combination Therapies Using Metformin and/or Valproic Acid in Prostate Cancer: Possible Mechanistic Interactions

2019 ◽  
Vol 19 (5) ◽  
pp. 368-381 ◽  
Author(s):  
Linh N.K. Tran ◽  
Ganessan Kichenadasse ◽  
Pamela J. Sykes
Keyword(s):  
Prostate Cancer ◽  
Valproic Acid ◽  
Androgen Receptor ◽  
Gene Fusion ◽  
Combination Therapies ◽  
Slowing Down ◽  
Castration Resistant ◽  
Local Pca ◽  
End Stage ◽  
Fusion Products

Prostate cancer (PCa) is the most frequent cancer in men. The evolution from local PCa to castration-resistant PCa, an end-stage of disease, is often associated with changes in genes such as p53, androgen receptor, PTEN, and ETS gene fusion products. Evidence is accumulating that repurposing of metformin (MET) and valproic acid (VPA) either when used alone, or in combination, with another therapy, could potentially play a role in slowing down PCa progression. This review provides an overview of the application of MET and VPA, both alone and in combination with other drugs for PCa treatment, correlates the responses to these drugs with common molecular changes in PCa, and then describes the potential for combined MET and VPA as a systemic therapy for prostate cancer, based on potential interacting mechanisms.

Propagation and plasma heating of the lower hybrid wave in the nonuniform density plasma

1979 ◽  
Vol 22 (8) ◽  
pp. 1533 ◽  
Author(s):  
Hirotada Abe ◽  
Ryohei Itatani ◽  
Hiromu Momota
Keyword(s):  
Plasma Heating ◽  
Lower Hybrid ◽  
Hybrid Wave ◽  
Lower Hybrid Wave ◽  
Density Plasma

Investigation of thermal and slowing-down alpha particles on JET using charge-exchange spectroscopy

1991 ◽  
Vol 33 (14) ◽  
pp. 1805-1824 ◽  
Author(s):  
M von Hellermann ◽  
W Mandl ◽  
H P Summers ◽  
A Boileau ◽  
R Hoekstra ◽  
...  
Keyword(s):  
Charge Exchange ◽  
Alpha Particles ◽  
Slowing Down ◽  
Exchange Spectroscopy

Collisional alpha transport in a weakly non-quasisymmetric stellarator magnetic field

2019 ◽  
Vol 85 (2) ◽  
Author(s):  
Peter J. Catto
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Boundary Layers ◽  
Collision Frequency ◽  
Alpha Particles ◽  
Slowing Down ◽  
Tail Distribution ◽  
Strong Motivation ◽  
Particle Confinement ◽  
Background Ions

Alpha particle confinement is a serious concern in stellarators and provides strong motivation for optimizing magnetic field configurations. In addition to the collisionless confinement of trapped alphas in stellarators, excessive collisional transport of the trapped alpha particles must be avoided while they tangentially drift due to the magnetic gradient (the $\unicode[STIX]{x1D735}B$ drift). The combination of pitch angle scatter off the background ions and the $\unicode[STIX]{x1D735}B$ drift gives rise to two narrow boundary layers in the trapped region. The first is at the trapped–passing boundary and enables the finite trapped response to be matched to the vanishing passing response of the alphas. The second layer is a region that encompasses the somewhat more deeply trapped alphas with vanishing tangential $\unicode[STIX]{x1D735}B$ drift. Away from (and between) these boundary layers, collisions are ineffective and the alpha $\unicode[STIX]{x1D735}B$ drift simply balances the small radial drift of the trapped alphas. As this balance does not vanish as the trapped–passing boundary is approached, the first collisional boundary layer is necessary and gives rise to $\surd \unicode[STIX]{x1D708}$ transport, with $\unicode[STIX]{x1D708}$ the collision frequency. The vanishing of the tangential drift results in a separate, somewhat wider boundary layer, and significantly stronger superbanana plateau transport that is independent of collisionality. The constraint imposed by the need to avoid significant energy depletion loss in the slowing down tail distribution function sets the allowed departure of a stellarator from an optimal quasisymmetric configuration.

scholarly journals Directional Track Selection Technique in CR39 SSNTD for lowyield reaction experiments

2018 ◽  
Vol 167 ◽  
pp. 05006 ◽  
Author(s):  
Francesco Ingenito ◽  
Pierluigi Andreoli ◽  
Dimitri Batani ◽  
Aldo Bonasera ◽  
Guillaume Boutoux ◽  
...  
Keyword(s):  
Cross Sections ◽  
Track Detector ◽  
Alpha Particles ◽  
Fusion Reactions ◽  
Particle Recognition ◽  
Low Energies ◽  
Nuclear Fusion Reactions ◽  
Fusion Products ◽  
Specific Experiment

There is a great interest in the study of p-11B aneutronic nuclear fusion reactions, both for energy production and for determination of fusion cross-sections at low energies. In this context we performed experiments at CELIA in which energetic protons, accelerated by the laser ECLIPSE, were directed toward a solid Boron target. Because of the small cross-sections at these energies the number of expected reactions is low. CR39 Solid-State Nuclear Track Detectors (SSNTD) were used to detect the alpha particles produced. Because of the low expected yield, it is difficult to discriminate the tracks due to true fusion products from those due to natural background in the CR39. To this purpose we developed a methodology of particle recognition according to their direction with respect to the detector normal, able to determine the position of their source. We applied this to the specific experiment geometry, so to select from all the tracks those due to particles coming from the region of interaction between accelerated protons and solid boron target. This technique can be of great help on the analysis of SSNTD in experiments with low yield reactions, but can be also generally applied to any experiment where particles reach the track detector with known directions, and for example to improve the detection limit of particle spectrometers using CR39.

High Density Plasma Heating by EC-Waves Injected from the High-Field Side for Mode Conversion to Electron Bernstein Waves in LHD

2013 ◽  
Vol 15 (2) ◽  
pp. 93-96 ◽  
Author(s):  
Y. Yoshimura ◽  
S. Kubo ◽  
T. Shimozuma ◽  
H. Igami ◽  
H. Takahashi ◽  
...  
Keyword(s):  
High Field ◽  
Mode Conversion ◽  
Plasma Heating ◽  
High Density ◽  
Bernstein Waves ◽  
Density Plasma

Ripple loss of suprathermal alpha particles during slowing-down in a tokamak reactor

1983 ◽  
Vol 23 (5) ◽  
pp. 657-665 ◽  
Author(s):  
K. Tani ◽  
T. Takizuka ◽  
M. Azumi ◽  
H. Kishimoto
Keyword(s):  
Alpha Particles ◽  
Tokamak Reactor ◽  
Slowing Down
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