Magnetic field line lengths inside interplanetary magnetic flux ropes

Hu, Qiang; Qiu, Jiong; Krucker, S.

doi:10.1002/2015ja021133

Cited by 57 publications

(78 citation statements)

References 50 publications

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“…Recent statistical studies (e.g., Hu et al 2015;Wang et al 2016) suggest that the distribution of the magnetic field line twist is clearly in contradiction with the Lundquist model discussed in Sect. 3.1.…”

Section: Twist In the Magnetic Cloudsmentioning

confidence: 82%

“…At larger distances from the centre the twist declined, i.e., the behaviour was opposite to that of the Lundquist model. Hu et al (2015) arrived at similar conclusions by utilising the field-line path lengths estimated from velocity dispersion in the arrival of solar energetic particles as well as from Grad-Shafranov reconstruction together with a constant-twist nonlinear forcefree Gold-Hoyle flux rope model (Gold and Hoyle 1960). The left-hand part of Fig.…”

Section: Twist In the Magnetic Cloudsmentioning

confidence: 99%

See 1 more Smart Citation

Coronal mass ejections and their sheath regions in interplanetary space

Kilpua

Koskinen

Pulkkinen

2017

Living Rev Sol Phys

366

386

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Interplanetary coronal mass ejections (ICMEs) are large-scale heliospheric transients that originate from the Sun. When an ICME is sufficiently faster than the preceding solar wind, a shock wave develops ahead of the ICME. The turbulent region between the shock and the ICME is called the sheath region. ICMEs and their sheaths and shocks are all interesting structures from the fundamental plasma physics viewpoint. They are also key drivers of space weather disturbances in the heliosphere and planetary environments. ICME-driven shock waves can accelerate charged particles to high energies. Sheaths and ICMEs drive practically all intense geospace storms at the Earth, and they can also affect dramatically the planetary radiation environments and atmospheres. This review focuses on the current understanding of observational signatures and properties of ICMEs and the associated sheath regions based on five decades of studies. In addition, we discuss modelling of ICMEs and many fundamental outstanding questions on their origin, evolution and effects, largely due to the limitations of single spacecraft observations of these macro-scale structures. We also present current understanding of space weather consequences of these large-scale solar wind structures, including effects at the other Solar System planets and exoplanets. We specially emphasize the different origin, properties and consequences of the sheaths and ICMEs.

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Section: Twist In the Magnetic Cloudsmentioning

confidence: 82%

Section: Twist In the Magnetic Cloudsmentioning

confidence: 99%

Coronal mass ejections and their sheath regions in interplanetary space

Kilpua

Koskinen

Pulkkinen

2017

Living Rev Sol Phys

366

386

View full text Add to dashboard Cite

show abstract

“…However, recent studies of field line twist and length distributions within magnetic flux-ropes in CMEs report inconsistencies with the Lundquist model. Hu et al (2015) showed that insitu measurements of interplanetary CMEs are consistent with a flux-rope structure with spiral field lines of constant and low twist. We use the latter finding for construction of the 3D configuration of magnetic field lines for our model.…”

Section: Modelmentioning

confidence: 86%

FRiED: A NOVEL THREE-DIMENSIONAL MODEL OF CORONAL MASS EJECTIONS

Isavnin

2016

ApJ

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We present a novel three-dimensional (3D) model of coronal mass ejections (CMEs) that unifies all key evolutionary aspects of CMEs and encapsulates their 3D magnetic field configuration. This fully analytic model is capable of reproducing the global geometrical shape of a CME with all major deformations taken into account, i.e., deflection, rotation, expansion, "pancaking", front flattening and rotational skew. Encapsulation of 3D magnetic structure allows the model to reproduce insitu measurements of magnetic field for trajectories of spacecraft-CME encounters of any degree of complexity. As such, the model can be used single-handedly for consistent analysis of both remote and in-situ observations of CMEs at any heliocentric distance. We demonstrate the latter by successfully applying the model for analysis of two CMEs.

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“…As a second flux-rope fitting model, we used the non-linear force-free Gold-Hoyle model (GH; Gold & Hoyle 1960) assuming a uniform field line twist (e.g. Farrugia et al 1999;Dasso et al 2006;Hu et al 2015). In this model, the radial functions of axial and poloidal field components are…”

Section: Gold-hoyle Versus Lundquist Modelsmentioning

confidence: 99%

Comparison of Magnetic Properties in a Magnetic Cloud and Its Solar Source on 2013 April 11–14

Vemareddy

Möstl

Amerstorfer

et al. 2016

ApJ

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In the context of Sun-Earth connection of coronal mass ejections and magnetic flux ropes (MFRs), we studied the solar active region (AR) and the magnetic properties of magnetic cloud (MC) event during April 14-15, 2013. We use in-situ observations from the Advanced Composition Explorer and source AR measurements from the Solar Dynamic Observatory. The MCs magnetic structure is reconstructed from the Grad-Shafranov method which reveals a northern component of the axial field with left-handed helicity. The MC invariant axis is highly inclined to the ecliptic plane pointing northward and is rotated by 117 o with respect to the source region PIL. The net axial flux and current in the MC are comparatively higher than from the source region. Linear force-free alpha distribution (10 −7 − 10 −6 m −1 ) at the sigmoid leg matches the range of twist number in the MC of 1-2 AU MFR. The MFR is non-linear force-free with decreasing twist from the axis (9 turns/AU) towards the edge. Therefore Gold-Hoyle (GH) configuration, assuming a constant twist, is more consistent with the MC structure than the Lundquist configuration of increasing twist from the axis to boundary. As an indication to that, the GH configuration yields better fitting to the global trend of in-situ magnetic field components, in terms of rms, than the Lundquist model. These cylindrical configurations improved the MC fitting results when considered the effect of self-similar expansion of MFR. For such twisting behaviour, this study suggests an alternative fitting procedure to better characterise the MC magnetic structure and its source region links.

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Magnetic field line lengths inside interplanetary magnetic flux ropes

Cited by 57 publications

References 50 publications

Coronal mass ejections and their sheath regions in interplanetary space

Coronal mass ejections and their sheath regions in interplanetary space

FRiED: A NOVEL THREE-DIMENSIONAL MODEL OF CORONAL MASS EJECTIONS

Comparison of Magnetic Properties in a Magnetic Cloud and Its Solar Source on 2013 April 11–14

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