Laboratory astrophysics in the extreme ultraviolet

Electron beam ion traps are uniquely well suited for laboratory astrophysics because they can produce nearly any charge state of any element in a collisionally excited plasma that is comparable in density and temperature to many astronomical sources. The Lawrence Livermore EBIT facility has been optimized for laboratory astrophysics with a suite of dedicated instruments and has made significant advances in this field. This paper reviews some of the work performed at LLNL in compiling comprehensive spectral catalogues, discovery of a magnetic field line diagnostic in the EUV and soft X-ray regimes, and density diagnostics on EBIT and at the NSTX tokamak.PACS Nos.: 95.30.Ky, 32.30.Rj, 95.75.–z, 95.85.Nv, 97.10.Ex, 95.55.Ka, 95.85.Mt, 52.55.Fa

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Ion acceleration, magnetic field line reconnection, and multiple current filament coalescence of a relativistic electron beam in a plasma

Physics of Plasmas ◽

10.1063/1.1484156 ◽

2002 ◽

Vol 9 (7) ◽

pp. 2959-2970 ◽

Cited By ~ 26

Author(s):

Jun-ichi Sakai ◽

Shinji Saito ◽

Hirokazu Mae ◽

Daniela Farina ◽

Maurizio Lontano ◽

...

Keyword(s):

Magnetic Field ◽

Electron Beam ◽

Field Line ◽

Relativistic Electron ◽

Magnetic Field Line ◽

Relativistic Electron Beam ◽

Ion Acceleration ◽

Current Filament

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Magnetic Field Reconnection in the Hα Eruptive Prominence on September 18, 1995

International Astronomical Union Colloquium ◽

10.1017/s0252921100047801 ◽

1998 ◽

Vol 167 ◽

pp. 310-313

Author(s):

Marian Karlický ◽

Pavel Kotrč ◽

Stanislava Šimberová ◽

Miloslav Knížek ◽

Michal Varady

Keyword(s):

Magnetic Field ◽

Detailed Analysis ◽

Field Line ◽

Magnetic Field Line ◽

Radio Burst ◽

Structural Changes ◽

Thermal Processes ◽

Eruptive Prominence ◽

X Ray

AbstractA violent evolution of the September 18, 1995 eruptive prominence is studied. The fast changes of the prominence structure started immediately after a weak radio burst on 3 GHz indicating the presence of non-thermal processes. A comparison with Yohkoh soft X-ray pictures was made. A detailed analysis of observations indicates magnetic field line reconnection, mainly in the space below the rising Hα prominence. The reconnection processes are manifested by structural changes of the Hα prominence and X-ray loops and also by the character of Doppler velocities in the Hα spectrum formed close to the reconnection space.

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X-ray wavelength survey of iron and nickel L-shell emission and resonance contributions to their intensities

Canadian Journal of Physics ◽

10.1139/p07-105 ◽

2008 ◽

Vol 86 (1) ◽

pp. 191-198 ◽

Cited By ~ 4

Author(s):

M F Gu

Keyword(s):

Electron Beam ◽

Lawrence Livermore National Laboratory ◽

National Laboratory ◽

Ion Traps ◽

Laboratory Astrophysics ◽

X Ray ◽

The Past ◽

Line Identification

As part of the laboratory astrophysics program at the electron beam ion traps of the Lawrence Livermore National Laboratory, L-shell X-ray emission of Fe and Ni ions have been studied extensively in the past decade. In this paper, we review these experimental efforts in line identification and wavelength surveys of Fe and Ni L-shell emission and resonance contributions to their intensities. PACS Nos.: 52.72.+v, 52.20.–j, 34.80.Kw

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Experimental Analysis of Merging Formation of a Field-Reversed Configuration by Use of Magnetic Field Line Tracing

IEEJ Transactions on Fundamentals and Materials ◽

10.1541/ieejfms.131.961 ◽

2011 ◽

Vol 131 (11) ◽

pp. 961-962

Author(s):

Keii Gi ◽

Toru Ii ◽

Yasushi Ono

Keyword(s):

Magnetic Field ◽

Field Line ◽

Magnetic Field Line ◽

Experimental Analysis ◽

Field Reversed Configuration

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Comparison of the measured and modelled electron densities and temperatures in the ionosphere and plasmasphere during 20-30 January, 1993

Annales Geophysicae ◽

10.1007/s00585-000-1257-6 ◽

2000 ◽

Vol 18 (10) ◽

pp. 1257-1262 ◽

Cited By ~ 1

Author(s):

A. V. Pavlov ◽

T. Abe ◽

K.-I. Oyama

Keyword(s):

Magnetic Field ◽

Heat Flux ◽

Electron Temperature ◽

Field Line ◽

Electron Density ◽

Magnetic Field Line ◽

New Approach ◽

Additional Heating ◽

Vibrational Levels ◽

The Magnetic Field

Abstract. We present a comparison of the electron density and temperature behaviour in the ionosphere and plasmasphere measured by the Millstone Hill incoherent-scatter radar and the instruments on board of the EXOS-D satellite with numerical model calculations from a time-dependent mathematical model of the Earth's ionosphere and plasmasphere during the geomagnetically quiet and storm period on 20–30 January, 1993. We have evaluated the value of the additional heating rate that should be added to the normal photoelectron heating in the electron energy equation in the daytime plasmasphere region above 5000 km along the magnetic field line to explain the high electron temperature measured by the instruments on board of the EXOS-D satellite within the Millstone Hill magnetic field flux tube in the Northern Hemisphere. The additional heating brings the measured and modelled electron temperatures into agreement in the plasmasphere and into very large disagreement in the ionosphere if the classical electron heat flux along magnetic field line is used in the model. A new approach, based on a new effective electron thermal conductivity coefficient along the magnetic field line, is presented to model the electron temperature in the ionosphere and plasmasphere. This new approach leads to a heat flux which is less than that given by the classical Spitzer-Harm theory. The evaluated additional heating of electrons in the plasmasphere and the decrease of the thermal conductivity in the topside ionosphere and the greater part of the plasmasphere found for the first time here allow the model to accurately reproduce the electron temperatures observed by the instruments on board the EXOS-D satellite in the plasmasphere and the Millstone Hill incoherent-scatter radar in the ionosphere. The effects of the daytime additional plasmaspheric heating of electrons on the electron temperature and density are small at the F-region altitudes if the modified electron heat flux is used. The deviations from the Boltzmann distribution for the first five vibrational levels of N2(v) and O2(v) were calculated. The present study suggests that these deviations are not significant at the first vibrational levels of N2 and O2 and the second level of O2, and the calculated distributions of N2(v) and O2(v) are highly non-Boltzmann at vibrational levels v > 2. The resulting effect of N2(v > 0) and O2(v > 0) on NmF2 is the decrease of the calculated daytime NmF2 up to a factor of 1.5. The modelled electron temperature is very sensitive to the electron density, and this decrease in electron density results in the increase of the calculated daytime electron temperature up to about 580 K at the F2 peak altitude giving closer agreement between the measured and modelled electron temperatures. Both the daytime and night-time densities are not reproduced by the model without N2(v > 0) and O2(v > 0), and inclusion of vibrationally excited N2 and O2 brings the model and data into better agreement.Key words: Ionosphere (ionospheric disturbances; ionosphere-magnetosphere interactions; plasma temperature and density)

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The development of magnetic field line wander by plasma turbulence

Journal of Plasma Physics ◽

10.1017/s0022377817000617 ◽

2017 ◽

Vol 83 (4) ◽

Cited By ~ 5

Author(s):

Gregory G. Howes ◽

Sofiane Bourouaine

Keyword(s):

Magnetic Field ◽

Field Line ◽

Magnetic Field Line ◽

Large Scale ◽

Magnetic Energy ◽

Plasma Turbulence ◽

Alfven Wave ◽

Astrophysical Plasmas ◽

Field Lines ◽

The Magnetic Field

Plasma turbulence occurs ubiquitously in space and astrophysical plasmas, mediating the nonlinear transfer of energy from large-scale electromagnetic fields and plasma flows to small scales at which the energy may be ultimately converted to plasma heat. But plasma turbulence also generically leads to a tangling of the magnetic field that threads through the plasma. The resulting wander of the magnetic field lines may significantly impact a number of important physical processes, including the propagation of cosmic rays and energetic particles, confinement in magnetic fusion devices and the fundamental processes of turbulence, magnetic reconnection and particle acceleration. The various potential impacts of magnetic field line wander are reviewed in detail, and a number of important theoretical considerations are identified that may influence the development and saturation of magnetic field line wander in astrophysical plasma turbulence. The results of nonlinear gyrokinetic simulations of kinetic Alfvén wave turbulence of sub-ion length scales are evaluated to understand the development and saturation of the turbulent magnetic energy spectrum and of the magnetic field line wander. It is found that turbulent space and astrophysical plasmas are generally expected to contain a stochastic magnetic field due to the tangling of the field by strong plasma turbulence. Future work will explore how the saturated magnetic field line wander varies as a function of the amplitude of the plasma turbulence and the ratio of the thermal to magnetic pressure, known as the plasma beta.

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