scholarly journals Sustainment of High-Beta Mirror Plasma by Neutral Beams

2018 ◽  
Vol 5 (3) ◽  
pp. 125-127
Author(s):  
T. D. Akhmetov ◽  
V. I. Davydenko ◽  
A. A. Ivanov ◽  
S. V. Murakhtin
Keyword(s):  
Magnetic Field ◽  
Plasma Pressure ◽  
Budker Institute ◽  
Maximum Plasma ◽  
Axially Symmetric ◽  
Field Reversal ◽  
Neutral Beams ◽  
Gas Dynamic ◽  
High Beta ◽  
Fast Ion

The report presents two experiments carried out in Budker Institute for obtaining the maximum plasma beta (ratio of the plasma pressure to magnetic field pressure) in axially symmetric magnetic field. The experiments are based on injection of powerful focused neutral beams with high neutral power density in the plasma. The produced fast ion population significantly increases the plasma pressure. It the axially symmetric GDT experiment (Gas Dynamic Trap) the plasma beta exceeded 0.6 at the fast ion turning points. The CAT experiment (Compact Axisymmetric Toroid) is being prepared for obtaining a plasmoid with extremely high diamagnetism in axially symmetric magnetic field. Reversal of magnetic field in the plasmoid is possible in this experiment.

Study of Microinstabilities in Anisotropic Plasmoid of Thermonuclear Ions

2009 ◽  
Vol 4 (1) ◽  
pp. 25-29
Author(s):  
Mariya S. Korzhavina ◽  
Andrey V. Anikeev ◽  
Petr A. Bagryansky
Keyword(s):  
Magnetic Field ◽  
Nuclear Physics ◽  
Field Vector ◽  
Budker Institute ◽  
Axially Symmetric ◽  
Plasma Parameters ◽  
Ion Density ◽  
Ion Cyclotron ◽  
Additional Section ◽  
Fast Ion

The following article presents the results of investigation of microinstabilities in the anisotropic synthesized hot ion plasmoid (SHIP). Plasmoid is located in a small mirror section that is installed at one side of the GDT facility in Budker Institute of Nuclear Physics, Novosibirsk, which is an axially symmetric magnetic mirror device of gas dynamic trap type. The magnetic field on axis is in the range of 2.5 Tesla and the mirror ratio is ~ 2. The additional mirror section is filled with background plasma streaming from the central cell of GDT. To create the population of hot ions with strong anisotropy two focused neutral beams with energy of 21–23 keV are injected perpendicularly to the direction of magnetic field. Ionisation of the beams generates the high-energetic ion component with the density of about 5x1013 сm–3 and mean energy about 13 keV. The distribution function of fast ions is thus strongly anisotropic in the phase space with the ratio E⊥ / E& ~ 50. To define the type and the parameters of the developing microinstability a set of high-frequency electrostatic and magnetic probes was used. The microinstability observed in the additional section of GDT is the Alfven ion cyclotron instability (AIC), because of small azimuthal wave numbers, magnetic field vector rotating in the direction of ion gyration and oscillation frequency below the actual ion cyclotron frequency. AIC instability threshold was registered at the following plasma parameters: fast ion density n > 3 · 1013 см–3, ratio of ion pressure to magnetic field pressure β ≈ 0.02, anisotropy A ≈ 35, ai / Rp ≈ 0.23, where ai is the ion gyroradius and Rp is the plasmoid radius.

Experimental Evidence of High-Beta Plasma Confinement in an Axially Symmetric Gas Dynamic Trap

2003 ◽  
Vol 90 (10) ◽  
Author(s):  
A. A. Ivanov ◽  
A. V. Anikeev ◽  
P. A. Bagryansky ◽  
P. P. Deichuli ◽  
S. A. Korepanov ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Axially Symmetric ◽  
Plasma Confinement ◽  
Gas Dynamic ◽  
High Beta

Kinetics of Fast Component and Energy Balance of the Plasma in Gas Dynamic System With Solenoidal Magnetic Field

2010 ◽  
Author(s):  
Alexei Chirkov ◽  
Sergey Kaskov
Keyword(s):  
Magnetic Field ◽  
Collision Operator ◽  
High Energy ◽  
Plasma Parameters ◽  
Magnetic Mirrors ◽  
Gas Dynamic ◽  
Barrier Formation ◽  
Maxwellian Plasma ◽  
Field Lines ◽  
Fast Ion

Numerical model of ion kinetics is considered for the axially symmetrical magnetic trap. Magnetic system of the trap consists of long solenoid and two end coils which constrict magnetic field lines and form so-called magnetic mirrors reflecting charged particles. The trap contains warm Maxwellian plasma and strongly non-Maxwellian high-energy (fast) ions. Steady-state fast ion population supported by the ionization of high-energy neutral atoms injected into the plasma. Physical model is based on the kinetic equation with two-dimensional Fokker–Planck collision operator in the velocity phase space. Regimes of plasma exhaust trough the mirrors are considered taking into account possibility of electrostatic barrier formation. Such regimes essentially differ from gas dynamic exhaust of the warm Maxwellian plasma. Parameters of power balance for the system under consideration are discussed.

Improved Regimes in High Pressure Magnetic Discharges

2010 ◽  
Author(s):  
Sergei V. Ryzhkov ◽  
Andrey V. Anikeev
Keyword(s):  
High Pressure ◽  
Energy Content ◽  
Radial Profile ◽  
High Energy ◽  
Plasma Pressure ◽  
Poloidal Magnetic Field ◽  
Gas Dynamic ◽  
Component Plasma ◽  
Field Lines ◽  
High Beta

Field-Reversed Configuration (FRC) [1] and Gas-Dynamic Trap (GDT) [2] represent compact system, which is a special magnetic geometry for plasma confinement. Theoretical and experimental study of gas-dynamic regimes with high energy content is carried out. The approach to a high beta (β is the ratio of plasma pressure to magnetic pressure) magnetic systems assumed different regimes of plasma with beta > 0.5 that is proper to compact devices such as tori and mirror traps. Both FRC and GDT traps are axial symmetric configurations, has open field lines and poloidal magnetic field only. Last experimental results on GDT have shown the possibility to build the stationary system with high beta. Analysis of the global energy and particle balance together with the Monte-Carlo equilibrium modelling allowed to conclude that two-component plasma confined in a steady-state regime. The characteristic plasma lifetimes are 4 to 5 times less then the experiment duration. A peripheral gas-puff near the mirror region enabled to maintain the radial profile of background plasma during the all neutral beam injection (NBI) pulse. This report is focused mainly on ambipolar effect and the possibility of further increasing the fast ion energy content and β. Improved gas-dynamic regimes in high pressure magnetic discharges and microinstabilities arising are described. Synthesized hot ion plasmoid (SHIP) experiment in the compact mirror section attached to the GDT central cell and the scheme of compact tori (FRC formation) for the compact mirror cell of GDT device are presented. Fusion prospects (reactor, neutron source, material studies) of such systems with high-energy (fast) particles [3, 4] and hybrid FRC + GDT scheme proposed by author from Bauman Moscow State Technical University (BMSTU) are discussed.

Solar Internal Rotation and Dynamo Waves: A Two-Dimensional Asymptotic Solution in the Convection Zone

2000 ◽  
Vol 179 ◽  
pp. 379-380
Author(s):  
Gaetano Belvedere ◽  
Kirill Kuzanyan ◽  
Dmitry Sokoloff
Keyword(s):  
Magnetic Field ◽  
Asymptotic Solution ◽  
Internal Rotation ◽  
Convection Zone ◽  
General Idea ◽  
Dynamo Model ◽  
Axially Symmetric ◽  
Dynamo Action ◽  
Regeneration Rate ◽  
Dynamo Waves

Extended abstractHere we outline how asymptotic models may contribute to the investigation of mean field dynamos applied to the solar convective zone. We calculate here a spatial 2-D structure of the mean magnetic field, adopting real profiles of the solar internal rotation (the Ω-effect) and an extended prescription of the turbulent α-effect. In our model assumptions we do not prescribe any meridional flow that might seriously affect the resulting generated magnetic fields. We do not assume apriori any region or layer as a preferred site for the dynamo action (such as the overshoot zone), but the location of the α- and Ω-effects results in the propagation of dynamo waves deep in the convection zone. We consider an axially symmetric magnetic field dynamo model in a differentially rotating spherical shell. The main assumption, when using asymptotic WKB methods, is that the absolute value of the dynamo number (regeneration rate) |D| is large, i.e., the spatial scale of the solution is small. Following the general idea of an asymptotic solution for dynamo waves (e.g., Kuzanyan & Sokoloff 1995), we search for a solution in the form of a power series with respect to the small parameter |D|–1/3(short wavelength scale). This solution is of the order of magnitude of exp(i|D|1/3S), where S is a scalar function of position.

Polar Magnetic Field Reversals of the Sun in Maunder Minimum

2000 ◽  
Vol 179 ◽  
pp. 193-196
Author(s):  
V. I. Makarov ◽  
A. G. Tlatov
Keyword(s):  
Magnetic Field ◽  
Maunder Minimum ◽  
The Sun ◽  
Annual Rings ◽  
Field Reversal ◽  
Polar Magnetic Field ◽  
Pine Trees ◽  
Using Data ◽  
Magnetic Field Reversal

AbstractA possible scenario of polar magnetic field reversal of the Sun during the Maunder Minimum (1645–1715) is discussed using data of magnetic field reversals of the Sun for 1880–1991 and the14Ccontent variations in the bi-annual rings of the pine-trees in 1600–1730 yrs.

Synchronized periodic maser flares of multiple OH and CH3OH lines in G323.459–0.079

2021 ◽  
Vol 502 (4) ◽  
pp. 5658-5667
Author(s):  
G C MacLeod ◽  
Derck P Smits ◽  
J A Green ◽  
S P van den Heever
Keyword(s):  
Magnetic Field ◽  
Excited State ◽  
Central Region ◽  
Time Lags ◽  
Field Reversal ◽  
Methanol Maser ◽  
Physical Conditions ◽  
Upper Limit ◽  
Methanol Masers ◽  
Magnetic Field Reversal

ABSTRACT The first confirmed periodically varying 6.031 and 6.035 GHz hydroxyl masers are reported here. They vary contemporaneously with the 6.7 GHz methanol masers in G323.459–0.079. The 1.665 GHz hydroxyl and 12.2  GHz methanol masers associated with G323.459–0.079 are also periodic. Evidence for periodicity is seen in all features in all transitions save a single 1.665 GHz hydroxyl maser feature. Historical excited-state hydroxyl maser observations set a stricter upper limit on the epoch in which a significant accretion event occurred. The associated burst in 6.7 GHz methanol maser activity has subsided significantly while the hydroxyl transitions are brightening possibly the result of changing physical conditions in the masing cloudlets. Time lags in methanol are confirmed and may be the result of the periodic flaring propagating outward from the central region of maser activity. A possible magnetic field reversal occurred during the accretion event.

scholarly journals Diffusion at the Earth magnetopause: enhancement by Kelvin-Helmholtz instability

2007 ◽  
Vol 25 (1) ◽  
pp. 271-282 ◽  
Author(s):  
R. Smets ◽  
G. Belmont ◽  
D. Delcourt ◽  
L. Rezeau
Keyword(s):  
Magnetic Field ◽  
Distribution Functions ◽  
Larmor Radius ◽  
Simple Analytical Model ◽  
Helmholtz Instability ◽  
Field Reversal ◽  
Finite Larmor Radius ◽  
The Earth ◽  
Specific Distribution ◽  
The Magnetic Field

Abstract. Using hybrid simulations, we examine how particles can diffuse across the Earth's magnetopause because of finite Larmor radius effects. We focus on tangential discontinuities and consider a reversal of the magnetic field that closely models the magnetopause under southward interplanetary magnetic field. When the Larmor radius is on the order of the field reversal thickness, we show that particles can cross the discontinuity. We also show that with a realistic initial shear flow, a Kelvin-Helmholtz instability develops that increases the efficiency of the crossing process. We investigate the distribution functions of the transmitted ions and demonstrate that they are structured according to a D-shape. It accordingly appears that magnetic reconnection at the magnetopause is not the only process that leads to such specific distribution functions. A simple analytical model that describes the built-up of these functions is proposed.

Motion of a charged particle in superposed Heliotron and biconical cusp fields

1969 ◽  
Vol 3 (2) ◽  
pp. 255-267 ◽  
Author(s):  
M. P. Srivastava ◽  
P. K. Bhat
Keyword(s):  
Magnetic Field ◽  
Charged Particle ◽  
Magnetic Moment ◽  
Particle Trajectory ◽  
Three Dimensional ◽  
Equation Of Motion ◽  
Neutral Point ◽  
Two Dimensional ◽  
Axially Symmetric ◽  
Hybrid Type

We have studied the behaviour of a charged particle in an axially symmetric magnetic field having a neutral point, so as to find a possibility of confining a charged particle in a thermonuclear device. In order to study the motion we have reduced a three-dimensional motion to a two-dimensional one by introducing a fictitious potential. Following Schmidt we have classified the motion, as an ‘off-axis motion’ and ‘encircling motion’ depending on the behaviour of this potential. We see that the particle performs a hybrid type of motion in the negative z-axis, i.e. at some instant it is in ‘off-axis motion’ while at another instant it is in ‘encircling motion’. We have also solved the equation of motion numerically and the graphs of the particle trajectory verify our analysis. We find that in most of the cases the particle is contained. The magnetic moment is found to be moderately adiabatic.

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