Note on the Helmholtz instability in stratified flows with magnetic fields

1983 ◽  
Vol 97 (1) ◽  
pp. 217-219
Author(s):  
A. Satya Narayanan
Keyword(s):  
Magnetic Fields ◽  
Stratified Flows ◽  
Helmholtz Instability

scholarly journals Magnetic field generation in a jet-sheath plasma via the kinetic Kelvin-Helmholtz instability

2013 ◽  
Vol 31 (9) ◽  
pp. 1535-1541 ◽  
Author(s):  
K.-I. Nishikawa ◽  
P. Hardee ◽  
B. Zhang ◽  
I. Duţan ◽  
M. Medvedev ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Magnetic Fields ◽  
Electric Field ◽  
Flow Direction ◽  
Transverse Magnetic ◽  
Velocity Shear ◽  
Helmholtz Instability ◽  
Magnetic Field Generation ◽  
Relativistic Jet

Abstract. We have investigated the generation of magnetic fields associated with velocity shear between an unmagnetized relativistic jet and an unmagnetized sheath plasma. We have examined the strong magnetic fields generated by kinetic shear (Kelvin–Helmholtz) instabilities. Compared to the previous studies using counter-streaming performed by Alves et al. (2012), the structure of the kinetic Kelvin–Helmholtz instability (KKHI) of our jet-sheath configuration is slightly different, even for the global evolution of the strong transverse magnetic field. In our simulations the major components of growing modes are the electric field Ez, perpendicular to the flow boundary, and the magnetic field By, transverse to the flow direction. After the By component is excited, an induced electric field Ex, parallel to the flow direction, becomes significant. However, other field components remain small. We find that the structure and growth rate of KKHI with mass ratios mi/me = 1836 and mi/me = 20 are similar. In our simulations saturation in the nonlinear stage is not as clear as in counter-streaming cases. The growth rate for a mildly-relativistic jet case (γj = 1.5) is larger than for a relativistic jet case (γj = 15).

Kelvin-Helmholtz instability in viscoelastic fluids in presence of electro-magnetic fields

2011 ◽  
Vol 23 (9) ◽  
pp. 094107 ◽  
Author(s):  
Amey S. Joshi ◽  
M. C. Radhakrishna ◽  
N. Rudraiah
Keyword(s):  
Magnetic Fields ◽  
Viscoelastic Fluids ◽  
Helmholtz Instability ◽  
Electro Magnetic

Physical effects of magnetic fields on the Kelvin-Helmholtz instability in a free shear layer

2018 ◽  
Vol 30 (4) ◽  
pp. 044102 ◽  
Author(s):  
Y. Liu ◽  
Z. H. Chen ◽  
H. H. Zhang ◽  
Z. Y. Lin
Keyword(s):  
Magnetic Fields ◽  
Shear Layer ◽  
Free Shear Layer ◽  
Helmholtz Instability ◽  
Physical Effects

scholarly journals Effect of Horizontal and Vertical Magnetic Fields on Kelvin?Helmholtz Instability

1968 ◽  
Vol 21 (6) ◽  
pp. 917 ◽  
Author(s):  
RC Sharma ◽  
KM Srivastava
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Combined Effect ◽  
Horizontal Motion ◽  
Helmholtz Instability ◽  
The Stability ◽  
Superposed Fluids ◽  
Oblique Magnetic Field

This paper discusses the effect of a general oblique magnetic field on the stability of two superposed fluids in relative horizontal motion. The stable and unstable cases at the interface (z = 0) between two uniform fluids with constant denRities and velocities of streaming are separately discussed. The combined effect of horizontal and vertical magnetic fields is to increase the wavelength at which the Kelvin-Helmholtz instability sets in.

scholarly journals Microscopic Processes In Global Relativistic Jets Containing Helical Magnetic Fields

2016 ◽  
Author(s):  
Kenichi Nishikawa ◽  
Yosuke Mizuno ◽  
Jacek Niemiec ◽  
Oleh Kobzar ◽  
Martin Pohl ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
General Structure ◽  
Microscopic Level ◽  
Relativistic Jets ◽  
Helmholtz Instability ◽  
Open Questions ◽  
Initial Evolution ◽  
Kinetic Instability ◽  
Helical Magnetic Field ◽  
Kinetic Instabilities

In the study of relativistic jets one of the key open questions is their interaction with the environment on the microscopic level. Here, we study the initial evolution of both electron–proton (e- - p+) and electron–positron (e±) relativistic jets containing helical magnetic fields, focusing on their interaction with an ambient plasma. We have performed simulations of "global" jets containing helical magnetic fields in order to examine how helical magnetic fields affect kinetic instabilities such as the Weibel instability, the kinetic Kelvin-Helmholtz instability (kKHI) and the Mushroom instability (MI). In our initial simulation study these kinetic instabilities are suppressed and new types of instabilities can grow. In the e- - p+ jet simulation recollimation-like instability occurs and jet electrons are strongly perturbed. In the e± jet simulation a recollimation-like instability occurs at early times followed by a kinetic instability and the general structure is similar to a simulation without helical magnetic field. Simulations using much larger systems are required in order to thoroughly follow the evolution of global jets containing helical magnetic fields.

Sign in / Sign up

Export Citation Format

Share Document