Генерация сверхальфвеновских сверхтепловых потоков плазмы в токовых слоях А.Г. Франк, Н.П. Кирий, С.Н. Сатунин Институт общей физики им. А.М. Прохорова.

Презентация:



Advertisements
Похожие презентации
Структура электродинамических сил, ускорение плазмы и генерация обратных токов в токовых слоях А.Г. Франк, Н.П. Кирий, С.Н. Сатунин Институт общей физики.
Advertisements

Plasma populations in the tail of induced magnetosphere O. Vaisberg Space Research Institute (IKI), Moscow, Russia, Talk outlay Mars missions studying.
The Pulse Generator for the Supersonic Flow Structure Control ГЕНЕРАТОР ИМПУЛЬСОВ ДЛЯ УПРАВЛЕНИЯ СТРУКТУРОЙ СВЕРХЗВУКОВОГО ПОТОКА Khristianovich Institute.
Физика плазмы в солнечной системе, ИКИ РАН, Влияние магнитного шира на «анизотропное» плазменное равновесие в хвосте магнитосферы Земли.
Special relativity. Special relativity (SR, also known as the special theory of relativity or STR) is the physical theory of measurement in an inertial.
Capacitance. Capacitance is the ability of a body to store an electrical charge. Any body or structure that is capable of being charged, either with static.
Electromagnetism. Electromagnetism is the branch of science concerned with the forces that occur between electrically charged particles. In electromagnetic.
Diffraction and Interference. Interference and Diffraction Distinguish Waves from Particles O The key to understanding why light behaves like waves is.
ON READINESS OF A TEACHER TO INNOVATIVE ACTIVITY Сухачева Т.В., Сухачев В.В. ФГОУ СПО «Минусинский сельскохозяйственный колледж», г. Минусинск Мельников.
7/23/2015 1:08:36 AMInno Course Contents1 For the Quantization Effects on the Spin Angular Momentum in presence of External magnetic Field VIEW the powerpoint.
Recent advances in intercalation compounds physics.
Coriolis effect. In physics, the Coriolis effect is a deflection of moving objects when they are viewed in a rotating reference frame. In a reference.
Genetics Genetics (from Ancient Greek γενετικός genetikos, "genitive" and that from γένεσις genesis, "origin"),[1][2][3] a discipline of biology, is the.
Maxwell's equations. Maxwell's equations are a set of partial differential equations that, together with the Lorentz force law, form the foundation of.
AFM-Raman and Tip Enhanced Raman studies of modern nanostructures Pavel Dorozhkin, Alexey Shchekin, Victor Bykov NT-MDT Co., Build. 167, Zelenograd Moscow,
Ionospheric model. Introduction Because of the complicated nature of the ionosphere, there have been numerous approaches for ionospheric modeling. In.
Vortex lattice in presence of weak periodic pinning potential W. V. Pogosov and V. V. Moshchalkov Laboratorium voor Vaste-Stoffysica en Magnetisme, K.
Instructions For Viewing Use Only Microsoft Powerpoint XP Version to Enable Effectively All the Animation Features in the Following Slides Spinning Ellipse.
PAT312, Section 7, December 2006 S7-1 Copyright 2007 MSC.Software Corporation SECTION 7 MSC.PATRAN GEOMETRY APPLICATION (PART III)
Gravitation. Gravitation, or gravity, is a natural phenomenon by which physical bodies attract with a force proportional to their masses. Gravitation.
Транксрипт:

Генерация сверхальфвеновских сверхтепловых потоков плазмы в токовых слоях А.Г. Франк, Н.П. Кирий, С.Н. Сатунин Институт общей физики им. А.М. Прохорова РАН VII Конференция по программе ОФН-15 РАН «Физика плазмы в солнечной системе» 6-10 февраля 2012 г.

Motivation Coronal mass ejections (CMEs) and solar flares are the most dramatic manifestations of the solar activity. These events origin in the active areas of the Sun, which have strong magnetic fields and a complicated structure. The energy liberated in the course of the CMEs and flares is the energy of non-potential magnetic fields, namely, the energy of electric currents in the solar corona. Laboratory experiments can shed light on a correlation between the structure of the magnetic fields and currents, on the one hand, and various effects of plasma dynamics, on the other hand, including generation of plasma jets. Our study is aimed at a search for such correlations on a basis of laboratory experiments carried out with the CS-3D device (3D Current Sheet) at the Institute of General Physics, Moscow.

= 2D magnetic field B = {h y; h x; 0} with the null-line at the z-axis, h 1 kG/cm; = Guide field B z is aligned with the null line: B z 8 kG; = Superposition of B and B z forms a 3D magnetic configuration with the X line; = Vacuum chamber, D = 18 cm, L = 100 cm, is filled with the neutral gas, He or Ar; = Initial plasma, N e 0 = cm -3, is produced by the -discharge; = Both magnetic fields and the initial plasma are uniform in the z-direction: /z = 0; = Current along the X line: J z 100 kA, T / 2 = 6 s, results in current sheet formation; = Diagnostics: magnetic probes, spectroscopic methods, holographic interferometry. Cross section of the CS-3D device AA, BB, CC – directions for magnetic probe displacements; Plasma radiation is collected from 2 cylindrical regions stretched along Oz-axis (D 1 =1.5 cm) and along Ox-axis (D 2 =2.5 cm)

Side view of the CS-3D device and the scheme of two-channel spectral measurements with the Nanogate 1-UF fast programmable CCD camera

Distributions of magnetic fields and current along the y-axis (the sheet thickness ) Distributions of magnetic fields and current along the x-axis (the sheet width ) 2 different sizes are typical for a distribution of the j z current in the (x,y) plane: x / y 6 15, i.e. a current sheet forms -B y 0 = -h x ByJByJ

Plasma jets can be generated in a current sheet under the action of the forces f x Compression of the current, plasma and the guide field B z into the sheet occurs under the action of the f Y forces

F x Ampere forces F x directed along the width of a current sheet h = 0.57 kG/cm Ar, 28 mTorr J z 100 kA; t 1.9 s А.Г. Франк, C.Н. Сатунин. Физика плазмы 37, 889 (2011) ByJByJ -B y 0 = -h x F x = -1/c (I z B y T ) B y T = B y 0 + B y J

Evolution of the ion temperature T i (1) and averaged energy of plasma jets W X (2) along the width of a current sheet: W X > T i t 4 s T i 40 eV, W X 85 eV, N i cm -3 v x cm/s v A cm/s v Ti 10 6 cm/s v x v A v Ti p = 28 mTorr; h = 0.5 kG/cm; J z 75 kA ArII nm

Plasma acceleration along the width of a current sheet M i N i dv/dt = - p + 1/c [j B] = p is negligible along the current sheet surface (x-direction). = In the 2D magnetic configurations (B z = 0) the Ampere forces f x сome to play only in the presence of a normal magnetic field component B y T : f x = 1/c [j B] x -1/c (j z B y T ) = The work of the Ampere forces f X (x) in a CS formed in the Ar plasma: ( f X (x) dx ) max N i W X eV cm -3 = Energy of accelerated Ar ions: W X max 85 eV; = Ion density in a CS midplane: N i cm -3, and N i 0 W X max eV cm -3 N i 0 W X max ( f X (x) dx ) max All Ar ions concentrated in a current sheet can be accelerated by the Ampere forces up to the energy W X 100 eV.

Energies of plasma flows W X, electron density and ion temperature in a current sheet formed in the He plasma He, 320 mTorr; h = 0.5 kG/cm; B z =0; J z max = 70 kA t 4.5 s W X > > T i W X 400 eV T i 50 eV SLs: HeII nm HeII nm Frank A.G. et al. Physics of Plasmas 18, (2011) v x cm/s v A cm/s v Ti cm/s v x v A v Ti

He, pressurep = 320 mTorrp = 100 mTorr Guide field B z = 0B z = 2.9 kGB z = 0B z = 2.9 kG N e 0, cm ± ± ± ± 0.1 N e x, cm ± ± ± 22.5 ± 0.9 T i, eV50 ± 5 50 ± 840 ± 10 W x, eV400 ± ± ± 40 t, μs 4.3 ± ± 0.4 Plasma jet energies W x in current sheets formed in He plasma Н.П. Кирий и др. Письма в ЖЭТФ 95, 17 (2012) ( f X (x) dx ) max N i W X eV cm -3 W x 400 eV N i cm -3 ; W x 1300 eV N i cm -3 ; N e cm -3 N i cm -3 ; N e cm -3 N i cm -3 Only a part of the He ions from a current sheet can be accelerated by the Ampere forces up to the energies W X 400 – 1300 eV.

Distributions of the current density j z (1), Ampere force f x (3), and plasma density N e (4) along the y-axis, at x = -5 cm A distribution N e (y) is very narrow as compared with a distribution f x (y), so that the plasma of lower density at wings of the N e (y) distribution can be effectively accelerated He, 320 mTorr h = 0.5 kG/ cm J z max = 70 kA Frank A.G. et al. Physics of Plasmas 18, (2011)

= Таким образом, ускорение плазмы в x направлении под действием сил Ампера может быть пространственно неоднородным в направлении нормали к поверхности слоя (ось y). = Наиболее эффективно плазма ускоряется на некотором расстоянии от средней плоскости слоя, при y 0, где силы f x (y) достаточно велики, а концентрация N e (y) существенно меньше, чем при y = 0. = Более плотная плазма, сосредоточенная в окрестности средней плоскости слоя, приобретает меньшую энергию. = В результате движения плазмы вдоль оси x становятся неоднородными вдоль оси y, т.е. приобретают характер сдвиговых течений. = Установлено, что продольное магнитное поле B z 0 препятствует ускорению (или движению) плазмы в x-направлении. Следовательно: B z 2 / 8π N i M i v x 2 / 2 = N i W x = При W x 400 eV N i cm -3 ; = При W x 1300 eV N i cm -3.

В чем различие между процессами ускорения ионов в токовых слоях, сформированных в Ar или в He плазме??? Силы вязкости при сдвиговых течениях: f visc - x f x visc y {[1.2 N i T i i ( ci i ) 2 ] v x y} f x visc [1.2 N i T i ( ci 2 i )] [v x ( y) 2 } Ar: ( ci i ) 2 1; f x visc f x Amp He: ( ci i ) 2 15 f x visc f x Amp f x visc B x (2); (3/2); Z i (1); N i (2); T i (1/2)

Заключение = Исследована эволюция параметров плазмы в токовых слоях, развивающихся в магнитных полях с X линией, в Ar и He плазме. = Обнаружена генерация потоков плазмы, которые движутся вдоль ширины (большего поперечного размера) токового слоя с энергиями, значительно превышающими тепловую энергию ионов плазмы. = Показано, что генерация сверхтепловых потоков обусловлена ускорением плазмы силами Ампера [j B] по направлению от середины токового слоя к его обоим боковым краям. = При формировании токовых слоев в Ar силы Ампера могут обеспечить ускорение всех ионов, сосредоточенных в слое, до энергий W X 100 эВ. = При формировании токовых слоев в He энергии плазменных потоков достигают W X эВ. В направлении нормали к поверхности токового слоя ускорение плазмы является пространственно неоднородным, т.е. движения плазмы приобретают характер сдвиговых течений. = Различия между ускорением плазмы в токовых слоях, развивающихся в Ar или в He, обусловлены, по-видимому, различным влиянием сил вязкости.

Спасибо за внимание!