Dynamical evolution of a magnetic cloud from the Sun to 5.4 AU

Nakwacki, M. S.; Dasso, S.; Démoulin, P.; Mandrini, C. H.; Gulisano, A. M.

doi:10.1051/0004-6361/201015853

Cited by 62 publications

(74 citation statements)

References 88 publications

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“…The MC 15 was also detected by ACE spacecraft at 1 AU. Its expansion rate was classical (ζ = 0.74, Nakwacki et al 2011). However, when the same MC is measured at 5.4 AU, it is strongly overtaken.…”

Section: Interacting Mcsmentioning

confidence: 88%

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Expansion of magnetic clouds in the outer heliosphere

Gulisano

Démoulin

Dasso

et al. 2012

A&A

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Context. A large amount of magnetized plasma is frequently ejected from the Sun as coronal mass ejections (CMEs). Some of these ejections are detected in the solar wind as magnetic clouds (MCs) that have flux rope signatures. Aims. Magnetic clouds are structures that typically expand in the inner heliosphere. We derive the expansion properties of MCs in the outer heliosphere from one to five astronomical units to compare them with those in the inner heliosphere. Methods. We analyze MCs observed by the Ulysses spacecraft using in situ magnetic field and plasma measurements. The MC boundaries are defined in the MC frame after defining the MC axis with a minimum variance method applied only to the flux rope structure. As in the inner heliosphere, a large fraction of the velocity profile within MCs is close to a linear function of time. This is indicative of a self-similar expansion and a MC size that locally follows a power-law of the solar distance with an exponent called ζ. We derive the value of ζ from the in situ velocity data. Results. We analyze separately the non-perturbed MCs (cases showing a linear velocity profile almost for the full event), and perturbed MCs (cases showing a strongly distorted velocity profile). We find that non-perturbed MCs expand with a similar non-dimensional expansion rate (ζ = 1.05 ± 0.34), i.e. slightly faster than at the solar distance and in the inner heliosphere (ζ = 0.91 ± 0.23). The subset of perturbed MCs expands, as in the inner heliosphere, at a significantly lower rate and with a larger dispersion (ζ = 0.28 ± 0.52) as expected from the temporal evolution found in numerical simulations. This local measure of the expansion also agrees with the distribution with distance of MC size, mean magnetic field, and plasma parameters. The MCs interacting with a strong field region, e.g. another MC, have the most variable expansion rate (ranging from compression to over-expansion).

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Section: Interacting Mcsmentioning

confidence: 88%

“…spacecraft is a rare event since it requires a close alignment of the spacecraft positions with the propagation direction of the MC (one case was analyzed by Nakwacki et al 2011). Nevertheless, the statistical evolution of S with D provides a constraint on the mean evolution of MCs.…”

Section: Global Radial Expansionmentioning

confidence: 99%

Expansion of magnetic clouds in the outer heliosphere

Gulisano

Démoulin

Dasso

et al. 2012

A&A

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“…Another example is the study aiming at relating the flux rope properties to the 3D configuration of its solar source in a more complete way than with timing, orientation, and magnetic flux (e.g. as realized in Nakwacki et al 2011, and references therein). So far, simplified methods have been developed to get estimations of some general MHD quantities contained in MCs, such as magnetic helicity (Dasso et al 2003(Dasso et al , 2006Dasso 2009) or magnetic energy (Nakwacki et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Global axis shape of magnetic clouds deduced from the distribution of their local axis orientation

Janvier

Démoulin

Dasso

2013

A&A

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Context. Coronal mass ejections (CMEs) are routinely tracked with imagers in the interplanetary space, while magnetic clouds (MCs) properties are measured locally by spacecraft. However, both imager and in situ data do not provide any direct estimation of the general flux rope properties. Aims. The main aim of this study is to constrain the global shape of the flux rope axis from local measurements and to compare the results from in-situ data with imager observations. Methods. We performed a statistical analysis of the set of MCs observed by WIND spacecraft over 15 years in the vicinity of Earth. We analyzed the correlation between different MC parameters and studied the statistical distributions of the angles defining the local axis orientation. With the hypothesis of having a sample of MCs with a uniform distribution of spacecraft crossing along their axis, we show that a mean axis shape can be derived from the distribution of the axis orientation. As a complement, while heliospheric imagers do not typically observe MCs but only their sheath region, we analyze one event where the flux rope axis can be estimated from the STEREO imagers.Results. From the analysis of a set of theoretical models, we show that the distribution of the local axis orientation is strongly affected by the overall axis shape. Next, we derive the mean axis shape from the integration of the observed orientation distribution. This shape is robust because it is mostly determined from the overall shape of the distribution. Moreover, we find no dependence on the flux rope inclination on the ecliptic. Finally, the derived shape is fully consistent with the one derived from heliospheric imager observations of the June 2008 event. Conclusions. We have derived a mean shape of MC axis that only depends on one free parameter, the angular separation of the legs (as viewed from the Sun). This mean shape can be used in various contexts, such as studies of high-energy particles or space weather forecasts.

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“…Such a great alignment between the Sun and both the spacecrafts provide us a unique opportunity to investigate the same ICME at two different evolution stages in the heliosphere. Skoug et al (2000), Du et al (2007), and Nakwacki et al (2011) have studied the dynamical evolution of the magnetic cloud macro-structure from the Sun to 5.4 au by analyzing the joint observations of this ICME event. Figure 1 shows the overview of the ICME observed by Wind and Ulysess.…”

Section: Evolution Of Alfvénic Fluctuations Inside the Icmementioning

confidence: 99%

Evolution of Alfvénic Fluctuations inside an Interplanetary Coronal Mass Ejection and Their Contribution to Local Plasma Heating: Joint Observations from 1.0 to 5.4 au

Wang

Richardson

et al. 2017

ApJL

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Directly tracking an interplanetary coronal mass ejection (ICME) by widely separated spacecrafts is a great challenge. However, such an event could provide us a good opportunity to study the evolution of embedded Alfvénic fluctuations (AFs) inside ICME and their contributions to local plasma heating directly. In this study, an ICME observed by Wind at 1.0 au on March 4-6 1998 is tracked to the location of Ulysess at 5.4 au. AFs are commonly found inside the ICME at 1.0 au, with an occurrence rate of 21.7% and at broadband frequencies from 4×10 −4 to 5×10 −2 Hz. When the ICME propagates to 5.4 au, the Aflvénicity decreases significantly, and AFs are rare and only found at few localized frequencies with the occurrence rate decreasing to 3.0%.At the same time, the magnetic field intensity at the AF-rich region has an extra 2 LI ET AL. magnetic dissipation except ICME expansion effect. The energetics of the ICME at different radial distance is also investigated here. Under similar magnetic field intensity situations at 1.0 au, the turbulence cascade rate at the AF-rich region is much larger than the value at the AF-lack region. Moreover, it can maintain as the decrease of magnetic field intensity if there is lack of AFs. However, when there exists many AFs, it reduces significantly as the AFs disappear. The turbulence cascade dissipation rate within the ICME is inferred to be 1622.3 J ·kg −1 ·s −1 , which satisfies the requirement of local ICME plasma heating rate, 1653.2 J · kg −1 · s −1 . We suggest that AF dissipation is responsible for extra magnetic dissipation and local plasma heating inside ICME.

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Dynamical evolution of a magnetic cloud from the Sun to 5.4 AU

Cited by 62 publications

References 88 publications

Expansion of magnetic clouds in the outer heliosphere

Expansion of magnetic clouds in the outer heliosphere

Global axis shape of magnetic clouds deduced from the distribution of their local axis orientation

Evolution of Alfvénic Fluctuations inside an Interplanetary Coronal Mass Ejection and Their Contribution to Local Plasma Heating: Joint Observations from 1.0 to 5.4 au

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