Challenges for plasma diagnostics in a next step device (FIRE)

In the framework of fusion energy research based on magnetic confinement, pulsed high-field tokamaks such as Alcator and FTU have made significant scientific contributions, while several others have been designed to reach ignition, but not built yet (IGNITOR, FIRE). Equivalent stellarator concepts, however, have barely been explored. The present study aims at filling this gap by: (1) performing an initial exploration of parameters relevant to ignition and of the difficulties for a highfield stellarator approach, and, (2) proposing a preliminary high-field stellarator concept for physics studies of burning plasmas and, possibly, ignition. To minimize costs, the device is pulsed, adopts resistive coils and has no blankets. Scaling laws are used to estimate the minimum field needed for ignition, fusion power and other plasma parameters. Analytical expressions and finite-element calculations are used to estimate approximate heat loads on the divertors, coil power consumption, and mechanical stresses as functions of the plasma volume, under wide-ranging parameters. Based on these studies, and on assumptions on the enhancement-factor of the energy confinement time and the achievable plasma beta, it is estimated that a stellarator of magnetic field B * 10 T and 30 m 3 plasma volume could approach or reach ignition, without encountering unsurmountable thermal or mechanical difficulties. The preliminary conceptual device is characterised by massive copper coils of variable cross-section, detachable periods, and a lithium wall and divertor.

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“…alpha-particle induced instabilities, alpha-particle losses and confinement). The FIRE tokamak diagnostics [85] are a reference for i-ASTER.…”

Section: Essential Diagnostics Strategymentioning

confidence: 99%

Initial Exploration of High-Field Pulsed Stellarator Approach to Ignition Experiments

Queral¹,

Volpe

Spong

et al. 2018

J Fusion Energ

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“…FIRE will need a comprehensive set of plasma and machine control diagnostics to carry out the mission. A preliminary set of diagnostics has been identified and a tentative assignment of ports has been made [15]. At this point in the design process, it has only been possible to consider conceptual aspects of the integration of diagnostics with the tokamak, its internal hardware and the necessary radiation shielding.…”

Section: Diagnosticsmentioning

confidence: 99%

FIRE, a next step option for magnetic fusion

Meade

2002

Fusion Engineering and Design

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The next major frontier in magnetic fusion physics is to explore and understand the strong non-linear coupling among confinement, MHD stability, self-heating, edge physics and waveparticle interactions that is fundamental to fusion plasma behavior. The Fusion Ignition Research Experiment (FIRE) design study has been undertaken to define the lowest cost facility to attain, explore, understand and optimize magnetically confined fusion-dominated plasmas. FIRE is envisioned as an extension of the existing advanced tokamak program that could lead to an attractive magnetic fusion reactor. FIRE activities have focused on the physics and engineering assessment of a compact, high-field tokamak with the capability of achieving Q ≈ 10 in the Elmy H-mode for a duration of ~ 1.5 plasma current redistribution times (skin times) during an initial burning plasma science phase, and the flexibility to add advanced tokamak hardware (e.g., lower hybrid current drive) later. The configuration chosen for FIRE is similar to that of ARIES-RS, the U. S. Fusion Power Plant study utilizing an advanced tokamak reactor. The key "advanced tokamak" features are: strong plasma shaping, double-null pumping divertors, low toroidal field ripple (< 0.3%), internal control coils and space for wall stabilization capabilities. The reference design point is R o = 2.14 m, a = 0.595 m, B t (R o) = 10T, I p = 7.7 MA with a flat top time of 20 s for 150 MW of fusion power. The baseline magnetic fields and pulse lengths can be provided by wedged BeCu/OFHC toroidal field (TF) coils and OFHC poloidal field (PF) coils that are pre-cooled to 80 K prior to the pulse and allowed to warm up to 373 K at the end of the pulse. A longer term goal of FIRE is to explore advanced tokamak regimes sustained by non-inductive current drive (e.g. lower hybrid current drive) at high fusion gain (Q > 5) for a duration of 1 to 3 current redistribution times.

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Physics basis and simulation of burning plasma physics for the fusion ignition research experiment (FIRE)

Kessel

Meade

Jardin

2002

Fusion Engineering and Design

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The FIRE design for a burning plasma experiment is described in terms of its physics basis and engineering features. Systems analysis indicates that the device has a wide operating space to accomplish its mission, both for the ELMing H-mode reference and the high bootstrap current/high β advanced tokamak regimes. Simulations with 1.5D transport codes reported here both confirm and constrain the systems projections. Experimental and theoretical results are used to establish the basis for successful burning plasma experiments in FIRE.

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Challenges for plasma diagnostics in a next step device (FIRE)

Cited by 3 publications

References 17 publications

Initial Exploration of High-Field Pulsed Stellarator Approach to Ignition Experiments

Initial Exploration of High-Field Pulsed Stellarator Approach to Ignition Experiments

FIRE, a next step option for magnetic fusion

Physics basis and simulation of burning plasma physics for the fusion ignition research experiment (FIRE)

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