E-Print Archive

There are 3872 abstracts currently viewable.


Advanced Search
Main Page Add New E-Print Submitter
News Help/FAQ About Preferences
Manage Key Phrase
Expansion of magnetic clouds in the outer heliosphere View all abstracts by submitter

Pascal Demoulin   Submitted: 2012-04-17 09:55

A large amount of magnetized plasma are frequently ejected from the Sun as Coronal Mass Ejections (CMEs). A part of these ejections are detected in the solar wind as magnetic clouds (MCs) which have flux rope signatures. MCs are typically expanding structures in the inner heliosphere. The aim of this work is to derive the expansion properties of MCs in the outer heliosphere from 1 to 5 AU and to compare them to the ones in the inner heliosphere. 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 implies a self-similar expansion and a MC size that locally follows a power-law of the solar distance with an exponent called zeta. We derive the value of zeta from the in situ velocity data. We analyze separately the non-perturbed MCs (cases presenting a linear velocity profile almost for the full event), and perturbed MCs (cases presenting a strongly distorted velocity profile). We find that non-perturbed MCs expand with a similar non-dimensional expansion rate (zeta = 1.05 ± 0.34), i.e. slightly faster than the solar distance and than in the inner heliosphere (zeta = 0.91± 0.23). The subset of perturbed MCs expands, as in the inner heliosphere, with a significant lower rate and with a larger dispersion (zeta = 0.28 ± 0.52) as expected from the temporal evolution found in numerical simulations. This local measure of the expansion is also in agreement with the distribution with distance of MC size, mean magnetic field and plasma parameters. The MCs in interaction with a strong field region, e.g. another MC, have the most variable expansion rate (ranging from compression to over-expansion).

Authors: A.M. Gulisano, P. Demoulin, S. Dasso, L. Rodriguez
Projects: None

Publication Status: in press, A&A
Last Modified: 2012-04-17 13:54
Go to main E-Print page  Solar origin of in-situ near-relativistic electron spikes observed with SEPT/STEREO  Observation and Simulation of Longitudinal Oscillations of an Active Region Prominence  Edit Entry  Download Preprint  Submitter's Homepage Delete Entry 

Go to main E-Print pageGo to main E-Print page.
Previous AbstractPrevious Abstract.
Next AbstractNext Abstract.
Download PreprintDownload Preprint.
Submitter's HomepageSubmitters Homepage.
Edit EntryEdit Entry.
View All Abstracts By SubmitterView all abstracts by submitter.
Delete AbstractDelete abstract.

Latest Entries
Two Episodes of Magnetic Reconnections During a Confined Circular-ribbon Flare
Enhanced stellar activity for slow antisolar differential rotation?
Quasi-periodic pulsations in the most powerful solar flare of Cycle 24
GONG Catalog of Solar Filament Oscillations Near Solar Maximum
Chromospheric response during the precursor and the main phase of a B6.4 flare on August 20, 2005
Unambiguous Evidence of Coronal Implosions During Solar Eruptions and Flares
Two Types of Long-duration Quasi-static Evolution of Solar Filaments
Oscillations of cometary tails: a vortex shedding phenomenon?
Observations of Running Penumbral Waves Emerging in a Sunspot
Reconnection in the Post-Impulsive Phase of Solar Flares
Temperature of source regions of 3He-rich impulsive solar energetic particles events
3He-rich Solar Energetic Particles in Helical Jets on the Sun
On the importance of the nonequilibrium ionization of Si IV and O IV and the line-of-sight in solar surges
Was the cosmic ray burst detected by the GRAPES-3 on 22 June 2015 caused by transient weakening of geomagnetic field or by an interplanetary anisotropy?
Connecting Coronal Mass Ejections to Their Solar Active Region Sources: Combining Results from the HELCATS and FLARECAST Projects
Studies of Isolated and Non-isolated Photospheric Bright Points in an Active Region Observed by the New Vacuum Solar Telescope
Fermi-LAT observations of the 2017 September 10th solar flare
Propagation of a global coronal wave and its interaction with large-scale coronal magnetic structures
A New Tool for CME Arrival Time Prediction Using Machine Learning Algorithms: CAT-PUMA
Solar Magnetoseismology with Magnetoacoustic Surface Waves in Asymmetric Magnetic Slab Waveguides

Related Pages
MSU Solar Physics.
Max Millennium Science Mail Archive.
Max Millennium Message of the Day Mail Archive.
Max Millennium Flare Catalog

Archive Maintainer
Alisdair Davey

© 2003 Solar Physics Group - Montana State University