Filaments in the edge confinement region of TJ-II

Nicolau, J. H.; Liu, B.; Grenfell, G.; Losada, U.; Carreras, B. A.; Garcia, L.; Hidalgo, C.

doi:10.1088/1741-4326/aa9db6

Cited by 6 publications

(4 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The line averaged density varied in the range n e ≈ 0.3-1.0 × 10 19 m −3 and the central electron temper ature in the range T e (0) = 300-400 eV. Two electrostatic Langmuir probes were used in the this experiment (figure 1) [15,16]. Probe B (at toroidal position φ = 195 • ) is inserted from the bottom of TJ-II, while probe D (at φ = 38 • ) is inserted from the top.…”

Section: Methodsmentioning

confidence: 99%

The impact of edge radial electric fields on edge–scrape-off layer coupling in the TJ-II stellarator

et al. 2019

View full text Add to dashboard Cite

In this letter, we investigate the impact of edge radial electric fields (Er) on turbulence propagation and the coupling between the plasma edge and the scrape-off layer (SOL) during slow electron–ion–electron root transitions in the TJ-II stellarator. The plasma edge was monitored with a set of electrostatic probes and Doppler reflectometry. It is shown, for the first time, that Er does not only affect the radial turbulence correlation length—a well-known effect—but it is also capable of reducing and nearly blocking the propagation of turbulence from the edge into the SOL. Specifically, in the ion root phase (Er < 0 in the edge), the SOL turbulence penetration depth was strongly reduced, as compared to the electron root phase (Er > 0). This result was obtained using a technique based on the transfer entropy, which quantifies the propagation of information. These observations are considered highly relevant in the framework of the understanding of the mechanisms that determine the SOL width, a vital parameter for future fusion reactors.

show abstract

Section: Methodsmentioning

confidence: 99%

The impact of edge radial electric fields on edge–scrape-off layer coupling in the TJ-II stellarator

et al. 2019

View full text Add to dashboard Cite

show abstract

“…In the experiments discussed here, the D probe was fitted with a two-dimensional probe head (with 4 × 5 pins laid out in a poloidal-radial grid), while the B probe was fitted with a rake probe (with 12 pins laid out in a radial array). For more details, please refer to [7]. TJ-II also disposes of a 2D carbon composite mushroomshaped electrode (12 mm high, with a diameter of 25 mm), installed on a fast reciprocating probe drive at ϕ = 174.4 • , entering from above.…”

Section: Probe Systemsmentioning

confidence: 99%

The impact of radial electric fields and plasma rotation on intermittence in TJ-II

Carreras¹,

Garcia²,

Grenfell³

et al. 2022

Plasma Phys. Control. Fusion

Self Cite

View full text Add to dashboard Cite

This work explores the impact of an imposed radial electric field on the intermittence parameter in magnetically confined plasmas. The intermittence is sensitive to both the magnetic configuration (dominant helical modes or low order rational surfaces) and to poloidal flows or radial electric fields. This behaviour was verified both in numerical turbulence calculations using a resistive MHD model and using Langmuir probe data obtained in experiments at the TJ-II stellarator. It is shown that the intermittence parameter can be used to detect when the local plasma rotation velocity with respect to the laboratory frame of reference is minimum.

show abstract

“…In the experiments discussed here, the D probe was fitted with a two-dimensional probe head (with 4 × 5 pins laid out in a poloidal-radial grid), while the B probe was fitted with a rake probe head (with 12 pins laid out in a radial array). For more details, please refer to [9]. In view of the following, we remark on the issue of the precision of the probe position and the magnetic configuration.…”

Section: Probe Systemsmentioning

confidence: 99%

The localization of low order rational surfaces based on the intermittence parameter in the TJ-II stellarator

Carreras¹,

Garcia²,

Hidalgo³

2020

Nucl. Fusion

View full text Add to dashboard Cite

This work intends to show that the multifractal concept of intermittence can be fruitfully applied to the identification of the radial location of low order rational surfaces inside a magnetically confined plasma. To do so, we make use of Langmuir probe data from a set of experiments in which the rotational transform was scanned dynamically in the TJ-II stellarator. It is shown that up to five rational surfaces can be identified from the data, which is a first in plasma physics, to the best of our knowledge. The effect of the radial electric field on intermittence was also studied using a specific subset of experiments in which the electron density was raised on a shot by shot basis. The observations are contrasted with results from numerical calculations using a resistive magneto-hydrodynamic model to facilitate interpretation.

show abstract

Filaments in the edge confinement region of TJ-II

Cited by 6 publications

References 19 publications

The impact of edge radial electric fields on edge–scrape-off layer coupling in the TJ-II stellarator

The impact of edge radial electric fields on edge–scrape-off layer coupling in the TJ-II stellarator

The impact of radial electric fields and plasma rotation on intermittence in TJ-II

The localization of low order rational surfaces based on the intermittence parameter in the TJ-II stellarator

Contact Info

Product

Resources

About