E-Print Archive

There are 4282 abstracts currently viewable.


Advanced Search
Main Page Add New E-Print Submitter
News Help/FAQ About Preferences
Manage Key Phrase
* News 04/04/20 * The archive is using a new backend database. This has thrown up a few SQL errors in the last few days. If you have any issues please email adavey@nso.edu with either the number of eprint you are trying to edit or a link to your preprint.

Re-analysis of Lepping's Fitting Method for Magnetic Clouds: Lundquist Fit Reloaded View all abstracts by submitter

Pascal Demoulin   Submitted: 2019-12-20 08:10

Magnetic clouds (MCs) are a subset of ejecta, launched from the Sun as coronal mass ejections. The coherent rotation of the magnetic field vector observed in MCs leads to envision MCs as formed by flux ropes (FRs). Among all the methods used to analyze MCs, Lepping's method (Lepping, Jones, and Burlaga, 1990, J. Geophys. Res. 95, 11957) is the broadest used. While this fitting method does not require the axial field component to vanish at the MC boundaries, this idea is largely spread in publications. Then, we revisit Lepping's method to emphasize its hypothesis and the meaning of its output parameters. As originally defined, these parameters imply a fitted FR which could be smaller or larger than the studied MC. We rather provide a re-interpretation of Lepping's results with a fitted model limited to the observed MC interval. We find that, typically the crossed FRs are asymmetric with a larger side both in size and magnetic flux before or after the FR axis. At the boundary of the largest side we find an axial magnetic field component distributed around 0 which we justify by the physics of solar eruptions. In contrast, at the boundary of the smaller side the axial field distribution is shifted to positive values, as expected with erosion acting during the interplanetary travel. This new analysis of Lepping's results have several implications. First, global quantities, such as magnetic fluxes and helicity, need to be revised depending on the aim (estimating global properties of FRs just after the solar launch or at 1 au). Second, the deduced twist profiles in MCs range quasi-continuously from nearly uniform, to increasing away from the FR axis, up to a reversal near the MC boundaries. There is no trace of outsider cases, but a continuum of cases. Finally, the impact parameter of the remaining FR crossed at 1 au is revised. Its distribution is compatible with weakly flatten FR cross-sections.

Authors: P. Demoulin, S. Dasso, M. Janvier, V. Lanabere
Projects: Wind

Publication Status: 2019, Solar Physics, 294, 172
Last Modified: 2019-12-21 23:20
Go to main E-Print page  A Magnetohydrodynamic Relaxation Method for Non-Force-Free Magnetic Field in Magnetohydrostatic Equilibrium  Excitation of decay-less transverse oscillations of coronal loops by random motions  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
Propagation Effects in Quiet Sun Observations at Meter Wavelengths
Twin Null-Point-Associated Major Eruptive Three-Ribbon Flares with Unusual Microwave Spectra
Trajectory Determination for Coronal Ejecta Observed by WISPR/Parker Solar Probe
Recurring Homologous Solar Eruptions in NOAA AR 11429
Resonant absorption: transformation of compressive motions into vortical motion
The depth and the vertical extent of the energy deposition layer in a medium-class solar flare
Helicity proxies from linear polarisation of solar active regions
The Submillimeter Active Region Excess Brightness Temperature during Solar Cycles 23 and 24
Nanoflare Diagnostics from Magnetohydrodynamic Heating Profiles
The Solar Orbiter mission - Science Overview
Time Series Analysis of Photospheric Magnetic Parameters of Flare-quiet versus Flaring Active Regions: Scaling Properties of Fluctuations
Image Quality Assessment for Full-Disk Solar Observations with Generative Adversarial Networks
Identifying and Tracking Solar Magnetic Flux Elements with Deep Learning
Active Region Irradiance During Quiescent Periods: New Insights from Sun-as-a-star Spectra
Probing solar flare accelerated electron distributions with prospective X-ray polarimetry missions
Accelerating and Supersonic Density Fluctuations in Coronal Hole Plumes: Signature of Nascent Solar Winds
Sequential Lid Removal in a Triple-Decker Chain of CME-Producing Solar Eruptions
RESIK and RHESSI observations of the 20 September 2002 flare
Starspot mapping with adaptive parallel tempering I: Implementation of computational code
Heating and Eruption of a Solar Circular Ribbon Flare

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

© 2000-2020 Solar Physics Group - Montana State University