Open boundary particle simulation of electrostatic ion cyclotron instability

1999 ◽  
Vol 61 (3) ◽  
pp. 407-414 ◽  
Author(s):  
SEIJI ISHIGURO ◽  
TETSUYA SATO ◽  
HISANORI TAKAMARU ◽  
Complexity Simulation Group
Keyword(s):  
Charged Particles ◽  
Potential Difference ◽  
Particle Simulation ◽  
Open Boundary ◽  
Time Step ◽  
Cyclotron Instability ◽  
Ion Cyclotron ◽  
Field Lines ◽  
The Magnetic Field ◽  
A Current

We have developed a 2½-dimensional open boundary particle simulation model and have studied the current-driven electrostatic ion-cyclotron instability and related d.c. potential difference. Fresh streaming electrons are injected smoothly from the boundaries at each time step, avoiding unphysical accumulation of charged particles in front of the boundaries. As a current-driven electrostatic ion cyclotron instability grows, a d.c. potential difference along the magnetic field lines is created.

Magnetic Field Aligned Potentials as an Acceleration Mechanism at Jupiter

2021 ◽  
Author(s):  
Dave Constable ◽  
Licia Ray ◽  
Sarah Badman ◽  
Chris Arridge ◽  
Chris Lorch ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Temporal Evolution ◽  
Charged Particles ◽  
Uniform Mesh ◽  
Time Varying ◽  
Potential Structure ◽  
Field Aligned Current ◽  
Field Lines ◽  
The Magnetic Field ◽  
Insight Into

<p>Since arriving at Jupiter, Juno has observed instances of field-aligned proton and electron beams, in both the upward and downward current regions. These field-aligned beams are identified by inverted-V structures in plasma data, which indicate the presence of potential structures aligned with the magnetic field. The direction, magnitude and location of these potential structures is important, as it affects the characteristics of any resultant field-aligned current. At high latitudes, Juno has observed potentials of 100’s of kV occurring in both directions. Charged particles that are accelerated into Jupiter’s atmosphere and precipitate can excite aurora; likewise, particles accelerated away from the planet can contribute to the population of the magnetosphere.</p> <p>Using a time-varying 1-D spatial, 2-D velocity space Vlasov code, we examine magnetic field lines which extend from Jupiter into the middle magnetosphere. By applying and varying a potential difference at the ionosphere, we can gain insight into the effect these have on the plasma population, the potential structure, and plasma densities along the field line. Utilising a non-uniform mesh, additional resolution is applied in regions where particle acceleration occurs, allowing the spatial and temporal evolution of the plasma to be examined. Here, we present new results from our model, constrained, and compared with recent Juno observations, and examining both the upward and downward current regions.</p>

Prototypes of a Field Disruption Energy Harvester

2012 ◽  
Author(s):  
Karim El-Rayes ◽  
Ahmed Abdel-Aziz ◽  
Eihab M. Abdel-Rahman ◽  
Raafat Mansour ◽  
Ehab El-Saadany
Keyword(s):  
Magnetic Field ◽  
Energy Source ◽  
Energy Harvesting ◽  
Energy Harvester ◽  
Low Frequency ◽  
Center Frequency ◽  
Field Source ◽  
Field Lines ◽  
The Magnetic Field ◽  
A Current

Energy harvesting from vibrations offers a prevailing non-traditional energy source. We introduce a novel electromagnetic transduction mechanism that can be used to harvest low-frequency vibrations. The mechanism induces a current in a coil by disrupting the electromagnetic field around the coil. The harvester is composed of a coil wound around track and surrounded by a magnetic field. The coil and magnetic field source remain stationary while a ferromagnetic ball material moves freely along the track cutting the field lines, disrupting the magnetic field, and inducing current in the coil. We present a prototype and experiments validating our energy harvesting mechanism as well as a model for the energy harvester. We find that our harvester can generate as much as 2mV and 21 μW from base vibrations of 0.9g amplitude. Our harvester demonstrates low-frequency harvesting with a center frequency as low as 9.4 Hz and a 3db harvesting bandwidth as wide as 5.8 Hz.

scholarly journals L-shell and energy dependence of magnetic mirror point of charged particles trapped in Earth’s magnetosphere

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Pankaj K. Soni ◽  
Bharati Kakad ◽  
Amar Kakad
Keyword(s):  
Magnetic Field ◽  
Charged Particles ◽  
Magnetic Mirror ◽  
Theoretical Expression ◽  
Neutral Atmosphere ◽  
Loss Cone ◽  
Field Lines ◽  
Mirror Point ◽  
The Magnetic Field ◽  
Shell Energy

Abstract In the Earth’s inner magnetosphere, there exist regions like plasmasphere, ring current, and radiation belts, where the population of charged particles trapped along the magnetic field lines is more. These particles keep performing gyration, bounce and drift motions until they enter the loss cone and get precipitated to the neutral atmosphere. Theoretically, the mirror point latitude of a particle performing bounce motion is decided only by its equatorial pitch angle. This theoretical manifestation is based on the conservation of the first adiabatic invariant, which assumes that the magnetic field varies slowly relative to the gyro-period and gyro-radius. However, the effects of gyro-motion cannot be neglected when gyro-period and gyro-radius are large. In such a scenario, the theoretically estimated mirror point latitudes of electrons are likely to be in agreement with the actual trajectories due to their small gyro-radius. Nevertheless, for protons and other heavier charged particles like oxygen, the gyro-radius is relatively large, and the actual latitude of the mirror point may not be the same as estimated from the theory. In this context, we have carried out test particle simulations and found that the L-shell, energy, and gyro-phase of the particles do affect their mirror points. Our simulations demonstrate that the existing theoretical expression sometimes overestimates or underestimates the magnetic mirror point latitude depending on the value of L-shell, energy and gyro-phase due to underlying guiding centre approximation. For heavier particles like proton and oxygen, the location of the mirror point obtained from the simulation deviates considerably (∼ 10°–16°) from their theoretical values when energy and L-shell of the particle are higher. Furthermore, the simulations show that the particles with lower equatorial pitch angles have their mirror points inside the high or mid-latitude ionosphere.

Measurements of RF-Induced SOL Modifications in Tore Supra Tokamak

2012 ◽  
Author(s):  
Martin Kubič ◽  
James P. Gunn ◽  
Laurent Colas ◽  
Stéphane Heuraux ◽  
Eric Faudot
Keyword(s):  
Magnetic Field ◽  
Radio Frequency ◽  
Flow Pattern ◽  
Current Flow ◽  
Power Ratio ◽  
Electrical Field ◽  
Ion Cyclotron ◽  
New Type ◽  
Field Lines ◽  
The Magnetic Field

Since spring 2011, one of the three ion cyclotron reconance heating (ICRH) antennas in the Tore Supra (TS) tokamak is equipped with a new type of Faraday screen (FS). Results from Radio Frequency (RF) simulations of the new Faraday screen suggest the innovative structure with cantilevered bars and ‘shark tooth’ openings significantly changes the current flow pattern on the front of the antenna which in turn reduces the RF potential and RF electrical field in particular parallel to the magnetic field lines which contributes to generating RF sheaths. Effects of the new FS operation on RF-induced scrape-off layer (SOL) modifications are studied for different plasma and antenna configurations — scans of strap power ratio imbalance, phasing, injected power and SOL density.

Geometry of magnetic field lines approaching a current sheet

2003 ◽  
Vol 69 (6) ◽  
pp. 541-550
Author(s):  
MANUEL NÚÑEZ
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Two Dimensions ◽  
Time Of Arrival ◽  
Positive Contribution ◽  
Neutral Sheet ◽  
Spatial Function ◽  
Field Lines ◽  
The Magnetic Field ◽  
A Current

The evolution of a magnetic field line in two dimensions near a neutral sheet is analysed. It is found that the general features of this evolution are rather independent of any particular model, provided that the magnetic field is small and the current density does not vanish. The time of arrival of a field line to the neutral sheet as well as its breaking and reconnection are proved to be finite and to satisfy a simple formula whose main parameter is the resistivity, which may be a spatial function. The shape of the evolving field lines satisfies a differential equation whose solution in some simple cases is shown to agree with certain classical reconnection configurations. Hyperresistivity is found to be more often a hindrance than a positive contribution to the reconnection process.

scholarly journals Cosmic Magnetic Fields and Superconducting Strings

1990 ◽  
Vol 140 ◽  
pp. 507-512 ◽  
Author(s):  
Christopher Thompson
Keyword(s):  
Magnetic Field ◽  
Galaxy Formation ◽  
Large Scale ◽  
Cosmic Ray ◽  
String Model ◽  
Maximum Energy ◽  
Superconducting Loop ◽  
Field Lines ◽  
The Magnetic Field ◽  
A Current

A cosmic magnetic field may play a significant role in the formation of galaxies and large scale structure. In particular, a fossil field of present strength ~ 10−9 Gauss is an essential ingredient in the superconducting string model of galaxy formation (Ostriker, Thompson and Witten 1986 (OTW); Thompson 1988a). We discuss the mechanism by which a current is induced on a superconducting string, including recent work on the reconnection of magnetic field lines near the string (Kulsrud and Thompson 1989). A substantial amount of baryonic plasma is trapped on the magnetic field lines which close around the string. The current on a loop almost certainly does not undergo exponential dynamo amplification; an oscillating superconducting loop emits a relativistic MHD wind (Thompson 1988a). Decaying superconducting loops fill most of the intergalactic medium with a relativistic, magnetized fluid. In this model, the gas between galaxies is highly clumped and strongly magnetized, the field strength approaching 1 μG. The maximum energy of cosmic ray protons accelerated at string-driven shocks is ~ 1020 eV (Madau and Thompson 1989).

Collisional effects on the electrostatic dust cyclotron instability

1999 ◽  
Vol 61 (1) ◽  
pp. 51-63 ◽  
Author(s):  
M. ROSENBERG ◽  
V. W. CHOW
Keyword(s):  
Magnetic Field ◽  
Kinetic Analysis ◽  
Dusty Plasma ◽  
Charged Dust ◽  
Cyclotron Instability ◽  
Weakly Ionized ◽  
The Magnetic Field ◽  
A Current

A kinetic analysis of the electrostatic dust cyclotron instability in a weakly ionized collisional dusty plasma is presented. In a plasma with negatively charged dust and a current along the magnetic field B, it is found that the instability can be excited by ions drifting along B. The effect of dust–neutral collisions is stabilizing, while the effect of ion–neutral collisions can be destabilizing. Possible applications to laboratory environments are discussed.

Cross field thermal transport in highly magnetized plasmas

1992 ◽  
Vol 437 (1899) ◽  
pp. 55-65 ◽  
Keyword(s):  
Magnetic Field ◽  
Heat Flux ◽  
Kinetic Equation ◽  
Mass Transport ◽  
Heat Transport ◽  
Electrostatic Interactions ◽  
Charged Particles ◽  
Non Local ◽  
Field Lines ◽  
The Magnetic Field

We construct a non-local kinetic equation for a plasma in a very strong magnetic field B where the charged particles coincide with their guiding centres and have zero drifts. It is shown that, although in this system mass transport occurs only along the field lines, heat transport cannot be confined only in the direction of the magnetic field. In particular, we estimate that a finite cross field heat flux scaling as 3/2 n ∂ T /∂ t = ∂( k ∞ ⊥ ∂ T /∂ x )∂ x ; k ∞ ⊥ = 3/2π ½ ( n 2 e 4 / m ½ T 3/2 ) L 2 ⊥ can be driven by collisions between like particles at the limit B → ∞. Hence, the classical B -2 dependence of k ⊥ must be modified to comply with this result. The choice of the cut-off length L ⊥ , representing the distance across B over which electrostatic interactions can be sustained, is discussed briefly at the end of the present work.

The Electrostatic Ion-Cyclotron Instability Excited by a Current to a Strip Collector

1986 ◽  
Vol 34 (6B) ◽  
pp. 821-824 ◽  
Author(s):  
J Juul Rasmussen ◽  
R Schrittwieser ◽  
Å Skøelv
Keyword(s):  
Cyclotron Instability ◽  
Ion Cyclotron ◽  
A Current
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