Energy confinement and magnetic field generation in the SSPX spheromak

Hudson, B.; Wood, R. D.; McLean, H. S.; Hooper, E. B.; Hill, D. N.; Jayakumar, J.; Moller, J.M.; Montez, D.F.; Romero-Talamás, C.A.; Casper, T.A.; Johnson, J. A.; LoDestro, L.L.; Mezonlin, Ephrem; Pearlstein, L. D.

doi:10.1063/1.2890121

Cited by 27 publications

(26 citation statements)

References 20 publications

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“…The SSPX facility at Lawrence Livermore National Laboratory is an experiment with its main purpose to investigate magnetic field buildup and energy confinement. 18 The spheromaks are confined within a cylindrical flux conserver with diameter of 1 m and height of 0.5 m. 19 The flux conserver is made of tungsten-coated copper walls with a separation at the midplane for diagnostic access. 20 The plasma discharges last a few milliseconds and achieve electron temperatures from about 10 eV up to over 500 eV, 18 and electron densities in the range of 10 13 -10 15 cm −3 .…”

Section: Spheromak Spectroscopymentioning

confidence: 99%

“…18 The spheromaks are confined within a cylindrical flux conserver with diameter of 1 m and height of 0.5 m. 19 The flux conserver is made of tungsten-coated copper walls with a separation at the midplane for diagnostic access. 20 The plasma discharges last a few milliseconds and achieve electron temperatures from about 10 eV up to over 500 eV, 18 and electron densities in the range of 10 13 -10 15 cm −3 . The SSPX diagnostics suite includes a Thomson scattering system, a CO 2 laser interferometer system, magnetic probes, and an ion doppler spectrometer, 20 which together with the SFFS make the SSPX spheromak a well-diagnosed experiment.…”

Section: Spheromak Spectroscopymentioning

confidence: 99%

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Grazing-incidence spectrometer on the SSPX spheromak

Clementson

Beiersdörfer

Magee

2008

Review of Scientific Instruments

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The silver flat field spectrometer (SFFS) is a high-resolution grazing-incidence diagnostic for magnetically confined plasmas. It covers the wavelength range of 25-450 A with a resolution of Delta lambda=0.3 A full width at half maximum. The SFFS employs a spherical 1200 lines/mm grating for flat-field focusing. The imaging is done using a backilluminated Photometrics charge-coupled device camera allowing a bandwidth of around 200 A per spectrum. The spectrometer has been used for atomic spectroscopy on electron beam ion traps and for plasma spectroscopy on magnetic confinement devices. Here we describe the design of the SFFS and the spectrometer setup at the sustained spheromak physics experiment in Livermore.

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Section: Spheromak Spectroscopymentioning

confidence: 99%

Section: Spheromak Spectroscopymentioning

confidence: 99%

Grazing-incidence spectrometer on the SSPX spheromak

Clementson

Beiersdörfer

Magee

2008

Review of Scientific Instruments

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“…[7], the homopolar generator in Figure 2 is identical with actual experiments creating "spheromaks" in which a capacitor-driven plasma gun replaces the generator. Spheromak experiments for magnetic fusion research inject current into a metal chamber for a time long compared to transit times across the chamber, with the goal of building up magnetic fields inside the chamber to values sufficient to confine high temperature plasmas [8]. Experiments devoted to astrophysics may focus on the formation and ejection of jets resembling the astrophysical structures in Figure 1 [9].…”

Section: Accelerator Structurementioning

confidence: 99%

On the Origin of Ultra High Energy Cosmic Rays II

Fowler¹,

Colgate²,

Li³

et al. 2011

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We show that accretion disks around Active Galactic Nuclei (AGN's) could account for the enormous power in observed ultra high energy cosmic rays ≈ 10 20 eV (UHE's). In our model, cosmic rays are produced by quasi-steady acceleration of ions in magnetic structures previously proposed to explain jets around Active Galactic Nuclei (AGN's) with supermassive black holes. Steady acceleration requires that an AGN accretion disk act as a dynamo, which we show to follow from a modified Standard Model in which the magnetic torque of the dynamo replaces viscosity as the dominant mechanism accounting for angular momentum conservation during accretion. A black hole of mass M BH produces a steady dynamo voltage V ∝ √M BH giving V ≈ 10 20 volts for M BH ≈ 10 8 solar masses. The voltage V reappears as an inductive electric field at the advancing nose of a dynamo-driven jet, where plasma instability inherent in collisionless runaway acceleration allows ions to be steadily accelerated to energies ≈ V, finally ejected as cosmic rays. Transient events can produce much higher energies. The predicted disk radiation is similar to the Standard Model. Unique predictions concern the remarkable collimation of jets and emissions from the jet/radiolobe structure. Given M BH and the accretion rate, the model makes 7 predictions roughly consistent with data: (1) the jet length; (2) the jet radius; (3) the steady-state cosmic ray energy spectrum; (4) the maximum energy in this spectrum; (5) the UHE cosmic ray intensity on Earth; (6) electron synchrotron wavelengths; and (7) the power in synchrotron radiation. These qualitative successes motivate new computer simulations, experiments and data analysis to provide a quantitative verification of the model.

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“…1 SSPX plasma currents achieved up to 1 MA, creating around 4 ms of plasma, with electron densities around 10 14 cm −3 and electron temperatures exceeding 500 eV. 2 A critical component of the Spheromak is the flux conserver, which is used to confine the plasma, and was made of Cu and coated with W to avoid sputtering of the wall material. 3 Impurities can play a beneficial role in plasmas, acting like a tracer, providing key information on plasma conditions through spectroscopical analysis.…”

Section: Introductionmentioning

confidence: 99%

Extreme ultraviolet spectroscopy and modeling of Cu on the SSPX Spheromak and laser plasma “Sparky”

Weller

Safronova

Clementson

et al. 2012

Review of Scientific Instruments

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Impurities play a critical role in magnetic fusion research. In large quantities, impurities can cool and dilute plasma creating problems for achieving ignition and burn; however in smaller amounts the impurities could provide valuable information about several plasma parameters through the use of spectroscopy. Many impurity ions radiate within the extreme ultraviolet (EUV) range. Here, we report on spectra from the silver flat field spectrometer, which was implemented at the Sustained Spheromak Physics experiment (SSPX) to monitor ion impurity emissions. The chamber within the SSPX was made of Cu, which makes M-shell Cu a prominent impurity signature. The Spect3D spectral analysis code was utilized to identify spectral features in the range of 115-315 Å and to more fully understand the plasma conditions. A second set of experiments was carried out on the compact laser-plasma x-ray∕EUV facility "Sparky" at UNR, with Cu flat targets used. The EUV spectra were recorded between 40-300 Å and compared with results from SSPX.

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Energy confinement and magnetic field generation in the SSPX spheromak

Abstract: The Sustained Spheromak Physics Experiment (SSPX) [E.B. Hooper, et. al., Nuclear Fusion, Vol. 39,No. 7] explores the physics of efficient magnetic field buildup and energy confinement,

Cited by 27 publications

References 20 publications

Grazing-incidence spectrometer on the SSPX spheromak

Grazing-incidence spectrometer on the SSPX spheromak

On the Origin of Ultra High Energy Cosmic Rays II

Extreme ultraviolet spectroscopy and modeling of Cu on the SSPX Spheromak and laser plasma “Sparky”

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