Model of quiescent prominence with the helical magnetic field

For understanding the effect of resonant helical magnetic field (RHF) and bias on the edge plasma turbulent transport, the radial and poloidal electric field (Er, EP), poloidal and toroidal magnetic field (BP, Br) were detected by the Langmuir probe, magnetic probe and diamagnetic loop. The poloidal, toroidal and radial velocity (VP, Vr, Vt) can be determined from the electric and magnetic field. In the present work, we have investigated the effect of the magnitude of bias (Vbias = 200v, Vbias = 320v) on Er, EP, BP, Bt, VP, Vr, Vt. Moreover, we applied RHF with L = 2, L = 3 and L = 2 and 3 and investigate the effect of the helical windings radius on above parameters. Also, the experiment was repeated by applying the positive biasing potentials and RHF's simultaneously. The results show that by applying bias to the plasma at t = 15 msec at r/a = 0.9, Er, BP and Bt increase while EP decreases. The best modification occurs at Vbias = 200v. By applying RHF to the plasma, both the electric and magnetic field vary. Er reaches the highest in the presence of RHF with L = 3. The same results are obtained for BP, Bt, VP and Vt. While the inverse results are obtained for EP and Vr. Finally, RHF and bias are applied simultaneously to the plasma. With applied bias with Vbias = 200v and RHF with L = 2 and 3, we reach to the ideal circumstance. The same results obtain in the situation with Vbias = 320v and RHF with L = 2 and 3.

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STATIONARY SHEATH OF FARADAY ROTATION IN THE JET OF 3C 120

International Journal of Modern Physics D ◽

10.1142/s0218271810016877 ◽

2010 ◽

Vol 19 (06) ◽

pp. 917-922

Author(s):

JOSÉ L. GÓMEZ ◽

MAR ROCA-SOGORB ◽

IVÁN AGUDO ◽

ALAN P. MARSCHER ◽

SVETLANA G. JORSTAD

Keyword(s):

Magnetic Field ◽

Faraday Rotation ◽

Radio Galaxy ◽

External Medium ◽

Degree Of Polarization ◽

Polarization Structure ◽

Rotation Measure ◽

Helical Magnetic Field ◽

3C 120 ◽

Two Fluid

We present a sequence of 12 monthly polarimetric multi-frequency VLBA observations of the radio galaxy 3C 120. The motion of multiple superluminal components allows the mapping of the polarization structure along most of the jet and across its width, revealing a coherent in time Faraday screen and RM-corrected polarization angles. Gradients in Faraday rotation and degree of polarization across the jet are observed, together with a localized region of high rotation measure superposed on this structure. This is explained as produced by the presence of a helical magnetic field in a two-fluid jet model, consisting of an inner emitting jet and a sheath containing nonrelativistic electrons. Interaction of the jet with the external medium would explain the confined region of enhanced Faraday rotation.

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The influence of a helical magnetic field on plasma ohmic heating in the S-1 machine

Journal of Nuclear Energy Part C Plasma Physics Accelerators Thermonuclear Research ◽

10.1088/0368-3281/8/6/319 ◽

1966 ◽

Vol 8 (6) ◽

pp. 757-763

Author(s):

P I Blinov ◽

B I Gavrilov ◽

P A Cheremnykh ◽

N M Yashin

Keyword(s):

Magnetic Field ◽

Ohmic Heating ◽

Helical Magnetic Field

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Thermal Cyclotron Radiation from a Hot Coronal Loop with Helical Magnetic Field

Fragmented Energy Release in Sun and Stars ◽

10.1007/978-94-011-1014-3_31 ◽

1994 ◽

pp. 225-231

Author(s):

O. A. Sheiner ◽

E. Ya. Zlotnik

Keyword(s):

Magnetic Field ◽

Coronal Loop ◽

Cyclotron Radiation ◽

Helical Magnetic Field ◽

Thermal Cyclotron Radiation

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Magnetized filament models for diverging plasma lenses

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa360 ◽

2020 ◽

Vol 493 (2) ◽

pp. 1736-1752

Author(s):

Adam Rogers ◽

Abdul Mohamed ◽

Bailey Preston ◽

Jason D Fiege ◽

Xinzhong Er

Keyword(s):

Magnetic Field ◽

Column Density ◽

Volume Density ◽

Magnetized Plasma ◽

Gravitational Lens ◽

Line Of Sight ◽

Density Distributions ◽

Rotation Measure ◽

Spherical Plasma ◽

Helical Magnetic Field

ABSTRACT Spherical plasma lens models are known to suffer from a severe overpressure problem, with some observations requiring lenses with central pressures up to millions of times in excess of the ambient interstellar medium. There are two ways that lens models can solve the overpressure problem: a confinement mechanism exists to counter the internal pressure of the lens, or the lens has a unique geometry, such that the projected column-density appears large to an observer. This occurs with highly asymmetric models, such as edge-on sheets or filaments, with potentially low volume–density. In the first part of this work we investigate the ability of non-magnetized plasma filaments to mimic the magnification of sources seen behind spherical lenses and we extend a theorem from gravitational lens studies regarding this model degeneracy. We find that for plasma lenses, the theorem produces unphysical charge density distributions. In the second part of the work, we consider the plasma lens overpressure problem. Using magnetohydrodynamics, we develop a non self-gravitating model filament confined by a helical magnetic field. We use toy models in the force-free limit to illustrate novel lensing properties. Generally, magnetized filaments may act as lenses in any orientation with respect to the observer, with the most high-density events produced from filaments with axes near the line of sight. We focus on filaments that are perpendicular to the line of sight that show the toroidal magnetic field component may be observed via the lens rotation measure.

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Relativistic Alfvén Waves on the jet of BL Lacertae

Proceedings of the International Astronomical Union ◽

10.1017/s1743921315002094 ◽

2014 ◽

Vol 10 (S313) ◽

pp. 147-152

Author(s):

Marshall H. Cohen ◽

David L. Meier

Keyword(s):

Magnetic Field ◽

Pitch Angle ◽

Lorentz Factor ◽

Alfven Waves ◽

Longitudinal Component ◽

Mhd Waves ◽

Alfvén Waves ◽

Bl Lacertae ◽

Pattern Speeds ◽

Helical Magnetic Field

AbstractThe jet of BL Lac displays transverse patterns that propagate downstream superluminally. We suggest that they are transverse Alfvén waves propagating on the longitudinal component of a helical magnetic field. The speed of the wave adds relativistically to the speed of the beam, and the apparent speed of the pattern is greater than the beam speed. Models for the jet and the MHD waves give values for the Lorentz factor of the beam of 3–4.4 and pitch angle of the helical magnetic field of 43° - 65°. These are consistent with other estimates, if the beam and pattern speeds are allowed to differ.

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