Results 21 to 30 of about 2,047 (170)

An adjoint method for neoclassical stellarator optimization [PDF]

Journal of Plasma Physics, 2019
Stellarators are a promising route to steady-state fusion power. However, to achieve the required confinement, the magnetic geometry must be highly optimized. This optimization requires navigating high-dimensional spaces, often necessitating the use of gradient-based methods.
Elizabeth J. Paul, Ian G. Abel, Matt Landreman, William Dorland   +3 more
openaire   +2 more sources

An Enhanced Evaluation Method of Sequential Probability Ratio Test

Mathematical Problems in Engineering, Volume 2019, Issue 1, 2019., 2019
Accurate event detection has high priority in many technical applications. Events in acquired data series, their duration, and statistical parameters provide useful information about the observed system and about its current state. This information can be used for condition monitoring, state identification, and many kinds of forecasting as well.
Gabor Gardonyi, Gabor Por, Krisztian Samu, Akhil Garg   +3 more
wiley   +1 more source

Suppression of non-axisymmetric field-induced α-particle loss channels in a quasi-axisymmetric stellarator

AIP Advances, 2022
In future fusion reactors, the confinement of α-particles is a crucial issue. The perfect omnigenity may be difficult to achieve in the quasi-isodynamic and quasi-symmetric stellarators when a multi-objective optimization is considered.
Yichao Zhang, Haifeng Liu, Jie Huang, Yuhong Xu, Jian Zhang, Akihiro Shimizu, Shinsuke Satake, Mitsutaka Isobe, Xianqu Wang, Jun Cheng, Hai Liu, Xin Zhang, Changjian Tang   +12 more
doaj   +1 more source

Collisionless microinstabilities in stellarators II - numerical simulations [PDF]

, 2013
Microinstabilities exhibit a rich variety of behavior in stellarators due to the many degrees of freedom in the magnetic geometry. It has recently been found that certain stellarators (quasi-isodynamic ones with maximum-$J$ geometry) are partly resilient
Helander, P., Proll, J. H. E., Xanthopoulos, P.   +2 more
core   +1 more source

Design of transverse magnetic field sweeping solenoids for 140 GHz mega‐watt gyrotrons

The Journal of Engineering, Volume 2018, Issue 14, Page 682-685, 2018., 2018
As the overlarge power density at the collector of mega‐watt (MW) gyrotrons limits the increase in their average output power and pulse width, transverse magnetic field sweeping solenoids (TMFSS) with periodical changing magnetic field have been designed for a 140 GHz MW gyrotron developed and tested at Beijing Vacuum Electronics Research Institute ...
Xu Zeng, Bentian Liu, Jinjun Feng
wiley   +1 more source

Global gyrokinetic simulations of ITG turbulence in the configuration space of the Wendelstein 7-X stellarator

, 2020
We study the effect of turbulent transport in different magnetic configurations of the Weldenstein 7-X stellarator. In particular, we performed direct numerical simulations with the global gyrokinetic code GENE-3D, modeling the behavior of Ion ...
Di Siena, A., Hindenlang, F., Jenko, F., Maurer, M., Merlo, G., Navarro, A. Bañón, Plunk, G. G., von Stechow, A., Wilms, F., Xanthopoulos, P.   +9 more
core   +1 more source

Greedy permanent magnet optimization

Nuclear Fusion, 2023
A number of scientific fields rely on placing permanent magnets in order to produce a desired magnetic field. We have shown in recent work that the placement process can be formulated as sparse regression.
Alan A. Kaptanoglu, Rory Conlin, Matt Landreman   +2 more
doaj   +1 more source

Quasi-symmetry in Stellarator Research 2. New Trend of Hellcal System Research [PDF]

, 2002
New trend is described on the basis of previous and on-going achievements. Magnetic shear is effective to stabilize ideal interchange modes, on the other hand magnetic well is needed for stabilization of resistive modes and micro-instabilities.
MATSUOKA Keisuke
core   +2 more sources

Stellarator optimization with constraints

Journal of Plasma Physics
In this work we consider the problem of optimizing a stellarator subject to hard constraints on the design variables and physics properties of the equilibrium. We survey current numerical methods for handling these constraints, and summarize a number of methods from the wider optimization community that have not been used extensively for stellarator ...
Rory Conlin, Patrick Kim, Daniel W. Dudt, Dario Panici, Egemen Kolemen   +4 more
openaire   +2 more sources

A quasi-isodynamic configuration with good confinement of fast ions at low plasma β

Nuclear Fusion, 2023
A new quasi-isodynamic (QI) stellarator configuration optimized for the confinement of energetic ions at low plasma β is obtained. The numerical optimization is carried out using the STELLOPT suite of codes.
E. Sánchez, J.L. Velasco, I. Calvo, S. Mulas   +3 more
doaj   +1 more source