E-Print Archive

There are 3812 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
Subject will be restored when possible View all abstracts by submitter

Pascal Demoulin   Submitted: 2008-06-02 11:08

In situ data provide only a one dimensional sample of the plasma velocity along the spacecraft trajectory crossing an interplanetary coronal mass ejection (ICME). Then, to understand the dynamics of ICMEs it is necessary to consider some model to describe it. We derive a series of equations in a hierarchical order, from more general to more specific cases, to provide a general theoretical basis for the interpretation of in situ observations, extending and generalizing previous studies. The main hypothesis is a self-similar expansion, but with the freedom of possible different expansion rates in three orthogonal directions. The most detailed application of the equations is though for a subset of ICMEs, magnetic clouds (MCs), where a magnetic flux rope can be identified. The main conclusions are the following ones. First, we obtain theoretical expressions showing that the observed velocity gradient within an ICME is not a direct characteristic of its expansion, but that it depends also on other physical quantities such as its global velocity and acceleration. The derived equations quantify these dependencies for the three components of the velocity. Second, using three different types of data we show that the global acceleration of ICMEs has, at most, a small contribution to the in situ measurements of the velocity. This eliminates practically one contribution to the observed velocity gradient within ICMEs. Third, we provide a method to quantify the expansion rate from velocity data. We apply it to a set of 26~MCs observed by Wind or ACE spacecrafts. They are typical MCs, and their main physical parameters cover the typical range observed in MCs in previous statistical studies. Though the velocity difference between their front and back includes a broad range of values, we find a narrow range for the determined dimensionless expansion rate. This implies that MCs are expanding at a comparable rate, independently of their size or field strength, despite very different magnitudes in their velocity profiles. Furthermore, the equations derived provide a base to further analyze the dynamics of MCs/ICMEs.

Authors: Demoulin, P., Nakwacki, M.S., Dasso, S., Mandrini, C.H.
Projects: None

Publication Status: in press, Solar Physics
Last Modified: 2008-06-03 09:13
Go to main E-Print page  Subject will be restored when possible  Expected in Situ Velocities from a Heirarchical Model for Exapnding Interplanetary Coronal Mass Ejections  Edit Entry  Download Preprint  Submitter's Homepage 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
Evolution of Photospheric Flow and Magnetic Fields Associated with The 2015 June 22 M6.5 Flare
Spatially inhomogeneous acceleration of electrons in solar flares
Probing Twisted Magnetic Field Using Microwave Observations in an M Class Solar Flare on 11 February, 2014
The origin, early evolution and predictability of solar eruptions
Polar Field Correction for HMI Line-of-Sight Synoptic Data
Relationship between Intensity of White-Light Flares and Proton Flux of Solar Energetic Particles
Spectroscopic Observations of a Current Sheet in a Solar Flare
IRIS Observations of Spicules and Structures Near the Solar Limb
Strong Transverse Photosphere Magnetic Fields and Twist in Light Bridge Dividing Delta Sunspot of Active Region 12673
Simultaneous observation of a flux rope eruption and magnetic reconnection during an X-class solar flare
Spectroscopic diagnostics of the non-Maxwellian κ-distributions using SDO/EVE observations of the 2012 March 7 X-class flare
Transient rotation of photospheric vector magnetic fields associated with a solar flare
Three-dimensional Forward-fit Modeling of the Hard X-Ray and Microwave Emissions of the 2015 June 22 M6.5 Flare
Center-to-Limb Variability of Hot Coronal EUV Emissions During Solar Flares
A time dependent relation between EUV solar flare light-curves from lines with differing formation temperatures
Understanding Breaks in Flare X-Ray Spectra: Evaluation of a Cospatial Collisional Return-current Model
Solar energetic particles and radio burst emission
A quasi-periodic fast-propagating magnetosonic wave associated with the eruption of a magnetic flux rope
Two-step solar filament eruptions
Regularized Biot-Savart Laws for Modeling Magnetic Flux Ropes

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