Physics basis for the Wisconsin HTS Axisymmetric Mirror (WHAM)
D. Endrizzi,
J.K. Anderson,
M. Brown
et al.
Abstract:The Wisconsin high-temperature superconductor axisymmetric mirror experiment (WHAM) will be a high-field platform for prototyping technologies, validating interchange stabilization techniques and benchmarking numerical code performance, enabling the next step up to reactor parameters. A detailed overview of the experimental apparatus and its various subsystems is presented. WHAM will use electron cyclotron heating to ionize and build a dense target plasma for neutral beam injection of fast ions, stabilized by … Show more
“…It should also be noted that a tokamak-based VNS option is presently explored, but alternative plasma configurations like stellarators and mirrors will also be investigated, if deemed attractive. As for the latter, important work is ongoing elsewhere (see [40]).…”
Section: Preliminary Results Of the Recent Exploration Of Feasible De...mentioning
The purpose of this paper is to critically review the testing and qualification strategy for the DEMO breeding blanket in Europe, identifying the potential risks and weaknesses and recommending, where necessary, the changes required to strengthen or accelerate the programme. Based on the information presented in this paper, a risk mitigation strategy is required to reduce the technological, licencing, and regulatory risks associated with the performance and reliability of the breeding blanket technologies for DEMO. An attractive mitigation option, which was originally proposed more than 30 years ago, but that was not implemented, is to perform testing and qualification of breeding blanket technologies and design concepts in a dedicated nuclear plasma device that serves as a 14 MeV Volumetric Neutron Source (VNS).
“…It should also be noted that a tokamak-based VNS option is presently explored, but alternative plasma configurations like stellarators and mirrors will also be investigated, if deemed attractive. As for the latter, important work is ongoing elsewhere (see [40]).…”
Section: Preliminary Results Of the Recent Exploration Of Feasible De...mentioning
The purpose of this paper is to critically review the testing and qualification strategy for the DEMO breeding blanket in Europe, identifying the potential risks and weaknesses and recommending, where necessary, the changes required to strengthen or accelerate the programme. Based on the information presented in this paper, a risk mitigation strategy is required to reduce the technological, licencing, and regulatory risks associated with the performance and reliability of the breeding blanket technologies for DEMO. An attractive mitigation option, which was originally proposed more than 30 years ago, but that was not implemented, is to perform testing and qualification of breeding blanket technologies and design concepts in a dedicated nuclear plasma device that serves as a 14 MeV Volumetric Neutron Source (VNS).
“…1978 a ; Endrizzi et al. 2023) (see item (D) below). We choose a conservative limit of while also noting higher values may be possible (GDT achieved ), acknowledging that the GDT vortex stabilization techniques have not yet been extended to the thermonuclear-grade parameters of a classical mirror when the confinement is much better.…”
Section: Size and Magnetic Field Requirements For Beammentioning
confidence: 99%
“…Blue lines are results from Egedal22, and dotted red lines are an empirical fit to the simulation results, where is the injection angle, is the loss cone pitch angle set by the mirror ratio and is a 5 beam half-width.Figure 3.The historical record of ion confinement time for simple mirror experiments as well as the predicted performance of WHAM (Endrizzi et al. 2023) and BEAM compared with predictions by (1.1). …”
Section: Introductionmentioning
confidence: 99%
“…The Wisconsin High-temperature-superconductor Axisymmetric Mirror experiment (WHAM) described in a companion paper by Endrizzi et al. (2023) (henceforth Endrizzi23) is an axisymmetric mirror intended, like BEAM, to operate in the weakly collisional or classical mirror regime similar to the earlier generation of experiments (see figure 3) built to address physics risks before embarking on a BEAM. The WHAM will provide a technology development platform for mirror fusion and in particular the next step device sketched in this paper.…”
Section: Introductionmentioning
confidence: 99%
“…The historical record of ion confinement time for simple mirror experiments as well as the predicted performance of WHAM (Endrizzi et al. 2023) and BEAM compared with predictions by (1.1). …”
This paper explores the feasibility of a break-even-class mirror referred to as BEAM (break-even axisymmetric mirror): a neutral-beam-heated simple mirror capable of thermonuclear-grade parameters and
$Q\sim 1$
conditions. Compared with earlier mirror experiments in the 1980s, BEAM would have: higher-energy neutral beams, a larger and denser plasma at higher magnetic field, both an edge and a core and capabilities to address both magnetohydrodynamic and kinetic stability of the simple mirror in higher-temperature plasmas. Axisymmetry and high-field magnets make this possible at a modest scale enabling a short development time and lower capital cost. Such a
$Q\sim 1$
configuration will be useful as a fusion technology development platform, in which tritium handling, materials and blankets can be tested in a real fusion environment, and as a base for development of higher-
$Q$
mirrors.
The paper presents an investigation of the plasma fluctuation in the SMOLA helical mirror, which is suspected to be responsible for anomalous scattering. The helical mirror confinement is effective when the ion mean free path is equal to the helix pitch length. This condition can be satisfied in hot collisionless plasma only by anomalous scattering. The wave, which scatters the passing ions, is considered to receive energy from the trapped ions. The oscillations of the electric field in the helically symmetric plasma were observed in experiment. The oscillations have both regular highly correlated and chaotic components. The dependency of the regular component frequency on the Alfvén velocity is linear for
$V_{\rm A} < 2.8 \times 10^6\ \text {m}\ \text {s}^{-1}$
and constant for higher values. It is shown experimentally that the condition for the wave to be in phase resonance with the trapped ions is satisfied in a specific region of the plasma column for the highly correlated component. The amplitude of the chaotic component (up to
$3\ \text {V}\ \text {cm}^{-1}$
) is higher than the estimated electric field required for the ion scattering.
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