Helicity conservation in expanding plasmas: Application to interplanetary magnetic clouds

1996 ◽  
Author(s):  
Ashok Kumar ◽  
D. M. Rust
Keyword(s):  
Magnetic Clouds ◽  
Helicity Conservation

scholarly journals Magnetic Helicity Conservation

2005 ◽  
Vol 13 ◽  
pp. 85-88 ◽  
Author(s):  
Mitchell A. Berger
Keyword(s):  
Interplanetary Space ◽  
Energy State ◽  
Minimum Energy ◽  
Free Field ◽  
Space Physics ◽  
Magnetic Clouds ◽  
Magnetic Helicity ◽  
Dynamo Theory ◽  
Mhd Turbulence ◽  
Helicity Conservation

AbstractMagnetic Helicity measures basic structural properties of magnetic fields such as twist, shear, linking, writhe, and handedness. It is conserved in ideal MHD and approximately conserved during reconnection. The minimum energy state of a field with a given magnetic helicity is a linear force free field. Helicity plays an important role in MHD turbulence and dynamo theory, and provides a valuable observational tool in solar and space physics. Helicity conservation can be tracked from the solar dynamo to active regions to coronal mass ejections to magnetic clouds in interplanetary space.

scholarly journals The magnetic helicity density patterns from non-axisymmetric solar dynamo

2021 ◽  
Vol 87 (1) ◽  
Author(s):  
Valery V. Pipin
Keyword(s):  
Magnetic Field ◽  
Differential Rotation ◽  
Conservation Law ◽  
Large Scale ◽  
Solar Dynamo ◽  
Magnetic Helicity ◽  
Dynamo Model ◽  
Density Distributions ◽  
Large Scale Magnetic Field ◽  
Helicity Conservation

We study the helicity density patterns which can result from the emerging bipolar regions. Using the relevant dynamo model and the magnetic helicity conservation law we find that the helicity density patterns around the bipolar regions depend on the configuration of the ambient large-scale magnetic field, and in general they show a quadrupole distribution. The position of this pattern relative to the equator can depend on the tilt of the bipolar region. We compute the time–latitude diagrams of the helicity density evolution. The longitudinally averaged effect of the bipolar regions shows two bands of sign for the density distributions in each hemisphere. Similar helicity density patterns are provided by the helicity density flux from the emerging bipolar regions subjected to surface differential rotation.

scholarly journals Flux rope axis geometry of magnetic clouds deduced from in situ data

2013 ◽  
Vol 8 (S300) ◽  
pp. 265-268
Author(s):  
Miho Janvier ◽  
Pascal Démoulin ◽  
Sergio Dasso
Keyword(s):  
Interplanetary Medium ◽  
Magnetic Cloud ◽  
Flux Rope ◽  
Magnetic Clouds ◽  
Direct Integration ◽  
Axis Orientation ◽  
In Situ Data ◽  
Geometrical Features ◽  
Wide Range

AbstractMagnetic clouds (MCs) consist of flux ropes that are ejected from the low solar corona during eruptive flares. Following their ejection, they propagate in the interplanetary medium where they can be detected by in situ instruments and heliospheric imagers onboard spacecraft. Although in situ measurements give a wide range of data, these only depict the nature of the MC along the unidirectional trajectory crossing of a spacecraft. As such, direct 3D measurements of MC characteristics are impossible. From a statistical analysis of a wide range of MCs detected at 1 AU by the Wind spacecraft, we propose different methods to deduce the most probable magnetic cloud axis shape. These methods include the comparison of synthetic distributions with observed distributions of the axis orientation, as well as the direct integration of observed probability distribution to deduce the global MC axis shape. The overall shape given by those two methods is then compared with 2D heliospheric images of a propagating MC and we find similar geometrical features.

scholarly journals Solar cycle evolution of the structure of magnetic clouds in the inner heliosphere

1998 ◽  
Vol 25 (15) ◽  
pp. 2959-2962 ◽  
Author(s):  
T. Mulligan ◽  
C. T. Russell ◽  
J. G. Luhmann
Keyword(s):  
Solar Cycle ◽  
Magnetic Clouds ◽  
Inner Heliosphere

Violation of both s- and t-channel helicity conservation from and LPS analysis of diffraction dissociation in πp → πππp

1972 ◽  
Vol 49 ◽  
pp. 441-457 ◽  
Author(s):  
J.V. Beaupré ◽  
M. Deutschmann ◽  
P. Finkler ◽  
H. Grässler ◽  
K.F. Albrecht ◽  
...  
Keyword(s):  
Diffraction Dissociation ◽  
Helicity Conservation

Magnetic clouds of oblate shapes

2005 ◽  
Vol 53 (1-3) ◽  
pp. 19-24 ◽  
Author(s):  
M. Vandas ◽  
E. Romashets ◽  
S. Watari
Keyword(s):  
Magnetic Clouds
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