Experimental Study of Hall Effect on a Formation Process of an FRC by Counter-Helicity Spheromak Merging in TS-4

Kaminou, Yasuhiro; Inomoto, Michiaki; Ono, Yasushi

doi:10.1585/pfr.11.2401052

Cited by 4 publications

(3 citation statements)

References 18 publications

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“…The reconnection region is affected through the appearance of a quadrupolar magnetic field, induced by the Hall current itself. This quadrupolar structure and so the Hall reconnection dynamics has been observed in the magnetosphere (Mozer, Bale & Phan 2002;Cattell et al 2005;Eastwood et al 2007;Frank, Artemyev & Zelenyi 2016), at the day-side magnetopause Vaivads et al (2004) and in the near-Earth magnetotail (Vaivads et al 2004;Borg et al 2005;Nakamura 2006), as well as in laboratory experiments (Cothran et al 2005;Ren et al 2005;Yamada et al 2006;Tharp et al 2013;Kaminou, Inomoto & Ono 2016). The current understanding of kinetic scales has been particularly improved thanks to the new observations from the Magnetospheric Multiscale (MMS) mission, whose data provides insight into the electron diffusion region in the proximity of the reconnection site , helping the numerical community.…”

Section: The Hall Effectmentioning

confidence: 74%

“…2006; Tharp et al. 2013; Kaminou, Inomoto & Ono 2016). The current understanding of kinetic scales has been particularly improved thanks to the new observations from the Magnetospheric Multiscale (MMS) mission, whose data provides insight into the electron diffusion region in the proximity of the reconnection site (Burch & Phan 2016), helping the numerical community.…”

Section: Onset Models Based On the Tearing Instability Of Thin Currenmentioning

confidence: 99%

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Onset of fast magnetic reconnection and particle energization in laboratory and space plasmas

et al. 2020

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The onset of magnetic reconnection in space, astrophysical and laboratory plasmas is reviewed discussing results from theory, numerical simulations and observations. After a brief introduction on magnetic reconnection and approach to the question of onset, we first discuss recent theoretical models and numerical simulations, followed by observations of reconnection and its effects in space and astrophysical plasmas from satellites and ground-based detectors, as well as measurements of reconnection in laboratory plasma experiments. Mechanisms allowing reconnection spanning from collisional resistivity to kinetic effects as well as partial ionization are described, providing a description valid over a wide range of plasma parameters, and therefore applicable in principle to many different astrophysical and laboratory environments. Finally, we summarize the implications of reconnection onset physics for plasma dynamics throughout the Universe and illustrate how capturing the dynamics correctly is important to understanding particle acceleration. The goal of this review is to give a view on the present status of this topic and future interesting investigations, offering a unified approach.

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Section: The Hall Effectmentioning

confidence: 74%

Section: Onset Models Based On the Tearing Instability Of Thin Currenmentioning

confidence: 99%

Onset of fast magnetic reconnection and particle energization in laboratory and space plasmas

et al. 2020

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“…Experimental studies [21,22,24,25] of the merging startup revealed the presence of a strong paramagnetic TF during the plasma formation [26]. In spite of the experimental results regarding the ST formation, there is no numerical work studying the plasma formation in detail.…”

Section: Introductionmentioning

confidence: 99%

2D Hall-MHD investigation of the magnetic pressure balance during merging start-up in spherical tokamaks

Ahmadi¹,

Ono²

2021

Nucl. Fusion

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In this work, the formation and merging of two spherical tokamak (ST) plasmas have been studied by the mean of the 2D Hall-MHD simulation. It was found that during the ST plasma formation, an internal toroidal field is formed due to the changes in the flux surface. The expanding force of this toroidal field pushes the formed STs toward the mid-plane just after the pinch-off, while the magnetic tension and mutual attraction of plasma toroids mainly drive the merging at the mid-plane. During the merging, the internal toroidal field doubles inside the separatrix due to the shrinking of the flux surface while the total toroidal and poloidal fluxes are conserved. After the merging, the single plasma goes through a relaxation process, reaching a force-free state.

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Numerical study of Hall effects on counter-helicity spheromak merging by two-dimensional Hall-MHD simulations

et al. 2017

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Hall effects on counter-helicity spheromak merging were investigated by two-dimensional MHD and Hall-MHD simulations of merging two axisymmetric toroidal flux tubes. In Hall-MHD cases, the structure of the reconnection current sheet and reconnection outflow are modified from the MHD case due to the Hall effect. We compared two cases (called “case-O” and “case-I”) of counter-helicity merging, which are distinguished by the polarity of toroidal magnetic fluxes. Radial motion of the reconnection X-point is controlled by poloidal electron flow accompanying the toroidal flux of the merging two spheromaks, and this creates a large difference in the current sheet and flow structure between the two cases of the Hall-MHD regime. The radial shift of the reconnection X-point depending on the polarity of toroidal magnetic flux of the spheromaks breaks the symmetry between the two cases. It was also found that there widely exists separation of ion and electron flow which are affected by the modification of the current sheet structure due to the radial shift of the X-point in the downstream side of the merging, and its spatial scale of the distribution of the Hall electric field is larger than the ion skin depth.

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Experimental Study of Hall Effect on a Formation Process of an FRC by Counter-Helicity Spheromak Merging in TS-4

Cited by 4 publications

References 18 publications

Onset of fast magnetic reconnection and particle energization in laboratory and space plasmas

Onset of fast magnetic reconnection and particle energization in laboratory and space plasmas

2D Hall-MHD investigation of the magnetic pressure balance during merging start-up in spherical tokamaks

Numerical study of Hall effects on counter-helicity spheromak merging by two-dimensional Hall-MHD simulations

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