E-Print Archive

There are 1713 abstracts currently viewable.


Search:

Advanced Search
Options
Main Page Add New E-Print Submitter
Information
Feedback
News Help/FAQ About Preferences
Manage Key Phrase
Notification
Global and local expansion of magnetic clouds in the inner heliosphere View all abstracts by submitter

Adriana Maria Gulisano   Submitted: 2009-09-29 02:55

Observations of magnetic clouds (MCs) are consistent with the presence of flux ropes detected in the solar wind (SW) a few days after their expulsion from the Sun as Coronal Mass Ejections (CMEs). Both, the in situ observations of plasma velocity profiles and the increase of their size with solar distance show that MCs are typically expanding structures. The aim of this work is to derive the expansion properties of MCs in the inner heliosphere from 0.3 to 1 AU. We analyze MCs observed by the two Helios spacecraft using in situ magnetic field and velocity measurements. We split the sample in two subsets: those MCs with a velocity profile that are significantly perturbed from the expected linear profile and those which are not. From the slope of the in situ measured bulk velocity along the Sun-Earth direction, we compute an expansion speed with respect to the cloud center for each of the analyzed MCs. We analyze how the expansion speed depends on the MC size, the translation velocity, and the heliocentric distance, finding that all MCs in the subset of non-perturbed MCs expand with almost the same non-dimensional expansion rate ($zeta$).We find departures from this general rule for $zeta$ only for perturbed MCs, and we interpret the departures as the consequence of a local and strong SW perturbation by SW fast streams, affecting the MC even inside its interior in addition to the direct interaction region between the SW and the MC. We also compute the dependence of the mean total SW pressure on the solar distance and we confirm that the decrease of the total SW pressure with distance is the main origin of the observed MC expansion rate. We found that $zeta$ was 0.91 +-0.23 for non-perturbed MCs while $zeta$ was 0.48 +- 0.79 for perturbed MCs, being the larger spread in the last ones due to the influence of solar wind local environment conditions on the expansion.

Authors: A. M. Gulisano, P. Démoulin, S. Dasso, M. E. Ruiz, and E. Marsch
Projects: None

Publication Status: Astronomy & Astrophysics, In press
Last Modified: 2009-09-30 08:09
Go to main E-Print page  Statistics of Flares Sweeping across Sunspots  Temporal variations of the CaXIX spectra in solar flares  Edit Entry  Download Preprint  Delete Entry 

Key
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
Statistical properties of H -alpha flares in relation to sunspots and active regions in the cycle 23
Diagnostics of energetic electrons with anisotropic distributions in solar flares I. Hard X-rays bremsstrahlung emission
On the Correlation between Spectra of Solar Microwave Bursts and Proton Fluxes near the Earth
Sun-as-a-Star, Chromospheric Lines, 1974-2009
FORMATION OF TORUS-UNSTABLE FLUX ROPES AND ELECTRIC CURRENTS IN ERUPTING SIGMOIDS
Resolving the Azimuthal Ambiguity in Vector Magnetogram Data with the Divergence-Free Condition: Application to Discrete Data
Minima of Solar Cycles 22/23 and 23/24 as Seen in SOHO/CELIAS/SEM Absolute Solar EUV Flux
HINODE OBSERVATIONS OF COHERENT LATERAL MOTION OF PENUMBRAL FILAMENTS DURING A X-CLASS FLARE
EUV SpectroPhotometer (ESP) in Extreme Ultraviolet Variability Experiment
The effect of wave-particle interactions on low energy cutoffs in solar flare electron spectra
Heliospheric Current Sheet Distortions from Adjacent Outflowing Transients: Multi-spacecraft Observations
A detailed investigation of the properties of a Vlasov-Maxwell equilibrium for the force-free Harris sheet}
On the Relationship between Equilibrium Bifurcations and Ideal MHD Instabilities for Line-Tied Coronal Loops}
Coronal Mass Ejections and Global Coronal Magnetic Field Reconfiguration
Relationship Between a Coronal Mass Ejection-Driven Shock and a Coronal Metric Type II Burst
An Intriguing Chromospheric Jet Observed by Hinode: I. Fine Structure Kinematics and Evidence of Unwinding Twists
A Code for Automated Tracing of Coronal Loops Approaching Visual Perception
Large Amplitude Oscillations in Prominences
An Extension of the Theory of Kinematic MHD Models of Collapsing Magnetic Traps to 2.5D with shear flow and to 3D
Confirming a Seismologically Inferred Coronal Temperature

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