Laboratory evidence for stationary inertial Alfvén waves

Koepke, M. E.; Finnegan, S. M.; Vincena, S.; Knudsen, D. J.; Nogami, S.H.; Vassiliadis, D.

doi:10.1088/0741-3335/58/8/084006

Cited by 3 publications

(1 citation statement)

References 12 publications

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“…220 Long-lived discrete auroral arcs have been proposed to be caused by stationary inertial Alfvén waves on the Earth's magnetic field, 221,222 and recent LAPD experiments have successfully generated a stationary inertial Alfvén wave in the laboratory frame. 223 An alternative idea is that propagating inertial Alfvén waves, generated along the plasma sheet boundary layer by magnetotail reconnection, propagate downward along the Earth's magnetic field toward to the high-latitude ionosphere and accelerate auroral electrons along their way. 153,[188][189][190][191] To test this hypothesis, recent experiments on the LAPD have launched inertial Alfvén waves down the 16 m cylindrical plasma column and measured the resulting perturbations of the parallel electron velocity distribution function using a novel whistler wave absorption diagnostic.…”

Section: Particle Accelerationmentioning

confidence: 99%

Laboratory space physics: Investigating the physics of space plasmas in the laboratory

Howes

2018

Physics of Plasmas

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Laboratory experiments provide a valuable complement to explore the fundamental physics of space plasmas without the limitations inherent to spacecraft measurements. Specifically, experiments overcome the restriction that spacecraft measurements are made at only one (or a few) points in space, enable greater control of the plasma conditions and applied perturbations, can be reproducible, and are orders of magnitude less expensive than launching spacecraft. Here I highlight key open questions about the physics of space plasmas and identify the aspects of these problems that can potentially be tackled in laboratory experiments. Several past successes in laboratory space physics provide concrete examples of how complementary experiments can contribute to our understanding of physical processes at play in the solar corona, solar wind, planetary magnetospheres, and outer boundary of the heliosphere. I present developments on the horizon of laboratory space physics, identifying velocity space as a key new frontier, highlighting new and enhanced experimental facilities, and showcasing anticipated developments to produce improved diagnostics and innovative analysis methods. A strategy for future laboratory space physics investigations will be outlined, with explicit connections to specific fundamental plasma phenomena of interest.

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Section: Particle Accelerationmentioning

confidence: 99%

Laboratory space physics: Investigating the physics of space plasmas in the laboratory

Howes

2018

Physics of Plasmas

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Plasma potential shaping using end-electrodes in the Large Plasma Device

Gueroult,

Tripathi,

Gaboriau

et al. 2024

J. Plasma Phys.

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We perform experiments in the Large Plasma Device at the University of California, Los Angeles, studying how different end-electrode biasing schemes modify the radial potential profile in the machine. We impose biasing profiles of different polarities and gradient signs on a set of five concentric electrodes placed 12 m downstream from the plasma source. We find that imposing concave-down profiles (negative potential radial gradient) on the electrodes creates radial potential profiles halfway up the plasma column that are comparable to those imposed on the electrodes and a few electron temperature in height, regardless of the biasing polarity. On the other hand, imposing concave-up profiles (positive potential radial gradient) leads to non-monotonic radial potential profiles. This observation can be explained by the current drawn through the electrodes and the parallel plasma resistivity, highlighting their important role in controlling the rotation of plasma. Concave-down plasma potential profiles, obtained by drawing electrons on the axis, are predicted to drive azimuthal drift velocities that can approach significant fractions of the ion sound speed in the central region of the plasma column.

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Particle-in-cell modelling of comet 67P/Churyumov-Gerasimenko

Gunell¹,

Goetz²

2023

A&A

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Context. Sufficiently far from the Sun, all comets go through a phase of low activity. Rosetta observations at large heliocentric distances of approximately 3 au showed that the plasma at a low-activity comet is affected by both steady state electric fields and low-frequency waves. Aims. Our goal is to provide a model for the electric fields in the inner coma at a low-activity comet and to simulate waves and field structures farther away from the nucleus. Methods. We compare analytical models for the convective, ambipolar, and polarisation electric fields to the results of an electrostatic particle-in-cell simulation of a scaled-down low-activity comet. Results. We find good agreement between the steady state field model and the simulation results close to the nucleus. At larger cometocentric distances, waves dominate the electric field. These waves are interpreted as the scaled-down electrostatic limit of the previously observed singing comet waves. The comet ion density is not spherically symmetric. Conclusions. Low-activity comets can be modelled using electrostatic particle-in-cell simulations of a scaled-down system. Outside the innermost part of the coma (r ≳ 40 km), the plasma is not spherically symmetric and the electric field is dominated by waves.

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Laboratory evidence for stationary inertial Alfvén waves

Cited by 3 publications

References 12 publications

Laboratory space physics: Investigating the physics of space plasmas in the laboratory

Laboratory space physics: Investigating the physics of space plasmas in the laboratory

Plasma potential shaping using end-electrodes in the Large Plasma Device

Particle-in-cell modelling of comet 67P/Churyumov-Gerasimenko

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