S. Togo

Neutral-density dependence of EIR- and MAR-dominated detachment regimes in hydrogen plasmas with multi-ion-temperature effects

Hiroki Natsume, H. Tanaka, S. Togo, K. Sawada et autres

A multi-ion-temperature model for hydrogen plasmas has been newly developed and implemented in the linear divertor plasma simulation code LINDA-NU to investigate detachment mechanisms involving atomic and molecular processes. In this model, H+, H2+, and H3+ ions are treated as separate fluids …

jp (code pays fourni par la source)

Experimental demonstration of RF-induced particle flux reduction using a toroidally localized electrode in a divertor-leg-like plasma

R. Ikezoe, Wooran Fumikawa, T. Onchi, Kazuaki Hanada et autres

Abstract Radio-frequency (RF) modification of edge plasma transport provides a potential pathway for active control of particle and heat fluxes in magnetically confined plasmas. In this study, we experimentally demonstrate RF-induced transport modification in a toroidal open-field-line plasma produced in QUEST, using …

jp (code pays fourni par la source)

RF-plugged divertor: impact of RF-induced effective potentials on SOL–divertor transport and particle loads

Wooran Fumikawa, R. Ikezoe, S. Togo

Abstract Mitigation of peak heat and particle loads on divertor targets remains a critical challenge for steady-state fusion reactors. Unlike conventional advanced divertor concepts that primarily rely on magnetic geometry modification, the radio-frequency (RF)-plugged divertor introduces a controllable field-aligned RF-induced effective potential …

jp (code pays fourni par la source)

Dynamic response of detached plasma to intermittent heat and particle fluxes induced by double-pulse ECH in GAMMA 10/PDX

Masayuki Yoshikawa, Junko KOHAGURA, Naomichi Ezumi, T. Kariya et autres

Abstract Detached plasma dynamics under transient upstream perturbations were investigated in the divertor simulation module of GAMMA 10/PDX using double-pulse central electron cyclotron heating (C-ECH) to generate controlled transient heat and particle fluxes. Detached plasma was produced by radiator gas injection, and …

jp, us, nl (code pays fourni par la source)

Machine-learning-based high-temporal-resolution electron temperature evaluation from photomultiplier tube signals in GAMMA 10/PDX: A tandem mirror plasma confinement device

T. Okamoto, Naomichi Ezumi, C. Masuya, Akihiro Kunii et autres

In this study, we propose a new method of electron temperature (Te) measurements with higher temporal resolution using a photomultiplier tube combined with machine learning (ML). It has been demonstrated that Te can be evaluated from Balmer series emissions Dα, Dβ, Dγ, …

jp (code pays fourni par la source)

Approximate Formulae Representing Effective-Charge-Number Dependence of Collisional Relaxation Coefficients for Electron Fluid Moment Equations in Open Magnetic Field System

Tomonori Takizuka, S. Togo

We study the collisional relaxation processes of electron fluid moments in open magnetic field systems, such as scrape-off layer and divertor plasmas, by using a simplified Fokker-Planck equation. Anisotropies in temperature and heat flux in directions parallel and perpendicular to the magnetic …

jp, ru (code pays fourni par la source)

A new approach to solve divertor heat and particle issues : RF plugging using a toroidally localized electrodes

R. Ikezoe, Wooran Fumikawa, S. Togo, T. Onchi et autres

MF2-10 Alternative divertors [Chair: Thomas Bosman] 16:30-18:40, Sep. 23 [404], MF2-10-I3

jp (code pays fourni par la source)

Discharge characteristics of a hybrid plasma source using hot cathode arc discharge and helicon wave discharge

Yuta Kinashi, Naomichi Ezumi, Takumi SETO, Reina Miyauchi et autres

Abstract High-density and large-diameter plasma generation is expected to contribute to semiconductor manufacturing, space propulsion, and nuclear fusion. We develop a plasma generation method for high-density, large-diameter plasma by combining the advantages of both hot cathode arc discharge and helicon wave discharge …

jp (code pays fourni par la source)

Temporal fluid simulation of plasma particle and energy confinement in GAMMA 10/PDX pellet injection experiments

Akihiro Kunii, S. Togo, Masayuki Yoshikawa, Naomichi Ezumi et autres

The pellet injection experiment in the tandem mirror device GAMMA 10/PDX is simulated with a plasma fluid model based on the anisotropic ion pressure (AIP model). A neutral gas shielding (NGS) model is implemented to model the pellet ablation rate. It is …

jp, ru (code pays fourni par la source)

Self-Consistent Establishment of the Bohm Criterion in Two-Ion-Species Plasmas Based on the Anisotropic-Ion-Pressure Plasma Fluid Scheme

S. Togo, T. Takizuka, H. Tanaka, R. Ikezoe et autres

The Bohm criterion for two-ion-species plasmas in a scrape-off layer–divertor system is investigated using the anisotropic-ion-pressure plasma fluid scheme and the virtual divertor model, which does not require the boundary condition of the incident flow speed at a divertor target. The flow …

jp, ru (code pays fourni par la source)

完全磁化プラズマのPICシミュレーションに向けたdouble leap-frog法の実装

Kazuma Emoto, S. Togo, Tomonori TAKIZUKA, I. Katanuma et autres

jp (code pays fourni par la source)

Behavior of detached simulation plasma by suddenly changed particle flux in GAMMA 10/PDX

Masayuki Yoshikawa, Junko KOHAGURA, Naomichi Ezumi, T. Kariya et autres

Plasma detachment is one of the most significant factors affecting nuclear fusion reactors. GAMMA 10/PDX has a divertor simulation experimental module (D-module) for detached plasma studies in the end region. To investigate the effect of suddenly changing the higher-density particle flux into …

jp, us, nl (code pays fourni par la source)