60 citations · 316 across the 14 of their papers we have counts for
14 papers
Radial electric field and density fluctuations measured by Doppler reflectometry during the post-pellet enhanced confinement phase in W7-X
T. Estrada, D. Carralero, T. Windisch +13
Radial profiles of density fluctuations and radial electric field, , have been measured using Doppler reflectometry during the post-pellet enhanced confinement phase achieved,…
On the role of density fluctuations in the core turbulent transport of Wendelstein 7-X
D. Carralero, T. Estrada, E. Maragkoudakis +19
A recent characterization of core turbulence carried out with a Doppler reflectometer in the optimized stellarator Wendelstein 7-X (W7-X) found that discharges achieving high ion t…
Physics design point of high-field stellarator reactors
J. A. Alonso, I. Calvo, D. Carralero +4
The ongoing development of electromagnets based on High Temperature Superconductors has led to the conceptual exploration of high-magnetic-field fusion reactors of the tokamak type…
An experimental characterization of core turbulence regimes in Wendelstein 7-X
D. Carralero, T. Estrada, E. Maragkoudakis +14
First results from the optimized helias Wendelstein 7-X stellarator (W7-X) have shown that core transport is no longer mostly neoclassical, as is the case in previous kinds of stel…
Characterization of the radial electric field and edge velocity shear in Wendelstein 7-X
D. Carralero, T. Estrada, T. Windisch +13
In this work we present the first measurements obtained by the V-band Doppler reflectometer during the second operation phase of Wendelstein 7-X to discuss the influence in the vel…
On-surface potential and radial electric field variations in electron root stellarator plasmas
J. M. García-Regaña, T. Estrada, I. Calvo +8
In the present work we report recent radial electric field measurements carried out with the Doppler reflectometry system in the TJ-II stellarator. The study focuses on the fact th…
The effect of tangential drifts on neoclassical transport in stellarators close to omnigeneity
Ivan Calvo, Felix I. Parra, J. L. Velasco +1
In general, the orbit-averaged radial magnetic drift of trapped particles in stellarators is non-zero due to the three-dimensional nature of the magnetic field. Stellarators in whi…
Flow damping in stellarators close to quasisymmetry
Ivan Calvo, Felix I. Parra, J. L. Velasco +1
Quasisymmetric stellarators are a type of optimized stellarators for which flows are undamped to lowest order in an expansion in the normalized Larmor radius. However, perfect quas…
Optimizing stellarators for large flows
Ivan Calvo, Felix I. Parra, J. Arturo Alonso +1
Plasma flow is damped in stellarators because they are not intrinsically ambipolar, unlike tokamaks, in which the flux-surface averaged radial electric current vanishes for any val…
When omnigeneity fails
Felix I. Parra, Ivan Calvo, Jose Luis Velasco +1
A generic non-symmetric magnetic field does not confine magnetized charged particles for long times due to secular magnetic drifts. Stellarator magnetic fields should be omnigeneou…
Stellarators close to quasisymmetry
Ivan Calvo, Felix I. Parra, J. L. Velasco +1
Rotation is favorable for confinement, but a stellarator can rotate at high speeds if and only if it is sufficiently close to quasisymmetry. This article investigates how close it…
Damping of radial electric field fluctuations in the TJ-II stellarator
J L Velasco, J A Alonso, I Calvo +8
The drift kinetic equation is solved for low density TJ-II plasmas employing slowly varying, time-dependent profiles. This allows to simulate density ramp-up experiments and to des…
Dynamics of zonal flow-like structures in the edge of the TJ-II stellarator
J. A. Alonso, J. L. Velasco, J. Arévalo +4
The dynamics of fluctuating electric field structures in the edge of the TJ-II stellarator, that display zonal flow-like traits, is studied. These structures have been shown to be…
Vanishing neoclassical viscosity and physics of the shear layer in stellarators
J. L. Velasco, J. A. Alonso, I. Calvo +1
The drift kinetic equation is solved for low density TJ-II plasmas employing slowly varying, time-dependent profiles. This allows to simulate density ramp-up experiments and descri…