Results 31 to 40 of about 415 (105)

Near-magnetic-axis geometry of a closely quasi-isodynamic stellarator [PDF]

Plasma Physics Reports, 2014
It is shown that the condition of stationary second adiabatic invariant at the magnetic axis of a stellarator configuration can be satisfied to good accuracy for all reflected particles.
Mikhailov, M., Nührenberg, J., Zille, R.   +2 more
openaire   +2 more sources

Direct construction of low-aspect-ratio advanced stellarators via asymptotic expansion

Nuclear Fusion
Advanced stellarators are promising candidates for fusion reactors due to their intrinsic steady-state operation capability and excellent plasma confinement properties.
Ke Liu, Zhexuan Zheng, Jianlin Peng, Caoxiang Zhu   +3 more
doaj   +1 more source

Evaluation of neoclassical transport in nearly quasi-isodynamic stellarator magnetic fields using MONKES

Nuclear Fusion
Stellarator magnetic fields that are perfectly optimized for neoclassical transport (with levels of radial neoclassical transport comparable to tokamaks) are called omnigenous.
F.J. Escoto, J.L. Velasco, I. Calvo, E. Sánchez   +3 more
doaj   +1 more source

Data-driven approach to model the influence of magnetic geometry in the confinement of fusion devices

Nuclear Fusion
Designing a fusion energy device to produce as much energy as possible requires balancing numerous physics constraints and metrics. In stellarators, the geometry is very flexible and involves a large number of free parameters.
R. Laia, R. Jorge, G. Abreu
doaj   +1 more source

Direct construction of optimized stellarator shapes. III. Omnigenity near the magnetic axis

, 2019
The condition of omnigenity is investigated, and applied to the near-axis expansion of Garren and Boozer (1991a). Due in part to the particular analyticity requirements of the near-axis expansion, we find that, excluding quasi-symmetric solutions, only ...
Helander, P., Landreman, M., Plunk, G. G.   +2 more
core   +1 more source

CIEMAT-QI4X: a reactor-relevant quasi-isodynamic stellarator configuration compatible with an island divertor

Nuclear Fusion
A four-field-period quasi-isodynamic stellarator configuration is presented that exhibits small neoclassical and electrostatic turbulent transport, good fast-ion confinement over a wide range of β values, small bootstrap current and an edge island ...
E. Sánchez, J.L. Velasco, I. Calvo, J.M. García-Regaña, C. Salcuni, J.A. Alonso   +5 more
doaj   +1 more source

Higher order theory of quasi-isodynamicity near the magnetic axis of stellarators

, 2023
The condition of quasi-isodynamicity is derived to second order in the distance from the magnetic axis. We do so using a formulation of omnigenity that explicitly requires the balance between the radial particle drifts at opposite bounce points of a ...
Plunk, Gabe G., Rodriguez, Eduardo
core   +1 more source

The residual flow in well-optimized stellarators

, 2023
The gyrokinetic theory of the residual flow, in the electrostatic limit, is revisited, with optimized stellarators in mind. We consider general initial conditions for the problem, and identify cases that lead to a non-zonal residual electrostatic ...
Helander, P., Plunk, G. G.
core  

Nonlinear simulations of core density collapses in large helical device

Nuclear Fusion
The stability of ballooning modes at the plasma edge of Stellarator fusion reactors is a major concern, considered a severe limiting factor of the device performance, particularly for low magnetic shear configurations based on quasi-isodynamic symmetry ...
J. Varela, Y. Takemura, K.Y. Watanabe, B. Breizman, F. Waelbroeck, D.A. Spong, L. Garcia, Y. Ghai, D. del Castillo-Negrete   +8 more
doaj   +1 more source

The Magnetic Gradient Scale Length Explains Why Certain Plasmas Require Close External Magnetic Coils

, 2023
The separation between the last closed flux surface of a plasma and the external coils that magnetically confine it is a limiting factor in the construction of fusion-capable plasma devices.
Kappel, John, Landreman, Matt, Malhotra, Dhairya   +2 more
core