The design and operation of the SPHEX spheromak

Rusbridge, M G; Gee, S J; Browning, Philippa; Cunningham, G.; Duck, R C; al-Karkhy, A; Martin, R.C.; Bradley, James W.

doi:10.1088/0741-3335/39/5/003

Cited by 47 publications

(67 citation statements)

References 39 publications

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“…The SPHEX experiment (Rusbridge (1996)) was operated at the University of Manchester from 1989 to 1997. The main issues considered were: the division of the plasma into a high electric field central column and a low electric field toroidal annulus; investigation of the global n=1 mode responsible for carrying energy and helicity from the central column to the annulus; the MHD dynamo responsible for current drive in the annulus.…”

Section: Present Experimentsmentioning

confidence: 99%

Assessment of Open Magnetic Fusion for Space Propulsion

Romanelli

Bruno

2006

57th International Astronautical Congress

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Abstract.The exploration of the solar system requires advanced propulsion techniques capable of specific impulse above 10 4 s and specific power in the range 1-10kW/kg. Fusion is the most interesting option to meet these requirements. Generic fusion propulsion studies, briefly reviewed in the report, show that specific power values in the desired range are indeed feasible provided a high fraction of the fusion power can be used for direct thrust. Open magnetic field configurations are particularly suited to such purpose. Their present status, open issues and proposals for space propulsion systems based on them are reviewed. The analysis is focused on mirrors (tandem mirror and gas-dynamic mirror), field reversed configurations, spheromaks and levitated dipole. Possible topics for further studies are proposed.

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Section: Present Experimentsmentioning

confidence: 99%

Assessment of Open Magnetic Fusion for Space Propulsion

Romanelli

Bruno

2006

57th International Astronautical Congress

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“…That quasi-steady ion acceleration can be initiated by MHD kink modes in the central column (or flux core) was demonstrated in the SPHEX spheromak experiment (Al-Karkhy et al 1993;Rusbridge et al 1997). Acceleration was attributed to MHD perturbations E 1 and B 1 , shown by measurement to be correlated to give an electric field parallel to the axisymmetrically averaged mean field B o , given by:…”

Section: T K Fowler and H LImentioning

confidence: 96%

Spheromaks and how plasmas may explain the ultra high energy cosmic ray mystery

Fowler

2016

J. Plasma Phys.

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In recent papers, we show how accretion disks around massive black holes could act as dynamos producing magnetic jets similar to the jets that create spheromaks in the laboratory. In this paper, we discuss how these magnetic astrophysical jets might naturally produce runaway ion beams accelerated to 10 20 eV or more, finally ejected as ultra high energy cosmic rays (UHECRs) long regarded as one of the mysteries of astrophysics. The acceleration is mainly due to the drift cyclotron loss cone kinetic instability known from plasma research. Experiments and simulations are suggested to verify the acceleration process.

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“…Summaries of the SPHEX project have recently appeared emphasizing the "rodomak" configuration [46], ion energy measurements [47], general SPHEX operation [48], the structure of the n=l mode [49], and the effects of instabilities in the plasma [SO].…”

Section: Collaborations and Contributors To The White Papermentioning

confidence: 99%

The Spheromak path to fusion energy

Hooper¹,

Barnes²,

Bellan³

1998

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The spheromak is a simple and robust magnetofluid configuration with several attractive reactor attributes including compact geometry, no material center post, high engineering p, and sustained steady state operation through helicity injection. Spheromak physics was extensively studied in the US program and abroad (especially Japan) in the 1980's with work continuing into the 1990s in Japan and the UK. Scientific results included demonstration of self-organization at constant helicity, control of the tilt and shift modes by shaped flux conservers, elucidation of the role of magnetic reconnection in the magnetic dynamo, and sustainment of a spheromak by helicity injection.Several groups attained electron temperatures above 100 eV in decaying plasmas, with CTX reaching 400 eV. This experiment had high magnetic field (>l T on the edge and -3 T near the symmetry axis) and good confinement. More recently, analysis of CTX found the energy confinement in the plasma core to be consistent with Rechester-Rosenbluth transport in a fluctuating magnetic field, potentially scaling to good confinement at higher electron temperatures. The SPHEX group developed an understanding of the dynamo in sustained spheromaks but in a relatively cold device. These and other physics results provide a foundation for a new "concept exploration" experiment to study the physics of a hot, sustained spheromak.If successful, this work leads to a next generation, proof-of-principle program.The new SSPX experiment will address the physics of a large-scale sustained spheromak in a national laboratory (LLNL) setting. The key issue in near term spheromak research will be to explore the possibly deleterious effects of sustainment on confinement.Other important issues include exploring the P scaling of confinement, scaling with Lundquist number S, and determining the need for active current-profile control. Collaborators from universities and other national laboratories are contributing experience from previous work, diagnostics, and physics support. Experiments at PPPL and Swarthmore are being conducted on the physics of magnetic reconnection, yielding physics results which should help advance the confinement work.A spheromak reactor will require steady state operation with the equilibrium fully supported by external coils. Although the present generation of experiments can provide data on the initial stages of the transition from short-pulsed operation, sustainment longer than the wall resistance time will be addressed in the proof-of-principle experiments.-lContents

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The design and operation of the SPHEX spheromak

Cited by 47 publications

References 39 publications

Assessment of Open Magnetic Fusion for Space Propulsion

Assessment of Open Magnetic Fusion for Space Propulsion

Spheromaks and how plasmas may explain the ultra high energy cosmic ray mystery

The Spheromak path to fusion energy

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