E-Print Archive

There are 4571 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
Scale-dependence of magnetic helicity in the solar wind View all abstracts by submitter

Axel Brandenburg   Submitted: 2012-04-01 23:18

We determine the magnetic helicity, along with the magnetic energy, at high latitudes using data from the Ulysses mission. The data set spans the time period from 1993 to 1996. The basic assumption of the analysis is that the solar wind is homogeneous. Because the solar wind speed is high, we follow the approach first pioneered by Matthaeus et al. by which, under the assumption of spatial homogeneity, one can use Fourier transforms of the magnetic field time series to construct one-dimensional spectra of the magnetic energy and magnetic helicity under the assumption that the Taylor frozen-in-flow hypothesis is valid. That is a well-satisfied assumption for the data used in this study. The magnetic helicity derives from the skew-symmetric terms of the three-dimensional magnetic correlation tensor, while the symmetric terms of the tensor are used to determine the magnetic energy spectrum. Our results show a sign change of magnetic helicity at wavenumber k ≈ 2 AU-1 (or frequency ν ≈ 2 μHz) at distances below 2.8 AU and at k ≈ 30 AU-1 (or ν ≈ 25 μHz) at larger distances. At small scales the magnetic helicity is positive at northern heliographic latitudes and negative at southern latitudes. The positive magnetic helicity at small scales is argued to be the result of turbulent diffusion reversing the sign relative to what is seen at small scales at the solar surface. Furthermore, the magnetic helicity declines toward solar minimum in 1996. The magnetic helicity flux integrated separately over one hemisphere amounts to about 1045 Mx2 cycle-1 at large scales and to a three times lower value at smaller scales.

Authors: Brandenburg, A., Subramanian, K., Balogh, A., & Goldstein, M. L.
Projects: None

Publication Status: Astrophys. J. 734, 9 (2011)
Last Modified: 2012-04-04 08:13
Go to main E-Print page  Energetic Particle Diffusion In Structured Turbulence  Multi-spacecraft Study of the 8 November 2000 SEP Event: Electron Injection Histories 100 Degrees Apart  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
Solar Radio Spikes and Type IIIb Striae Manifestations of Sub-second Electron Acceleration Triggered by a Coronal Mass Ejection
Statistical study of Type III bursts and associated HXR emissions
On orbit performance of the solar flare trigger for the Hinode EUV Imaging Spectrometer
Plasma Composition Measurements in an Active Region from Solar Orbiter/SPICE and Hinode/EIS
Modulation of cosmic ray anti-protons in the heliosphere: simulations for a solar cycle
Temporal and spatial association between microwaves and type III bursts in the upper corona
Prospective Implications of EUV Coronal Plumes for Magnetic-network Genesis of Coronal Heating, Coronal-hole Solar Wind, and Solar-wind Magnetic-field Switchbacks
Solar Energetic Particle Events with Short and Long Onset Times
The mechanism of magnetic flux rope rotation during solar eruption
Quantification of the Writhe Number Evolution of Solar Filament Axes
Starspot mapping with adaptive parallel tempering. II. Application to TESS data for M-dwarf flare stars, AU Microscopii, YZ Canis Minoris, and EV Lacertae
A Superflare on YZ Canis Minoris Observed by Seimei Telescope and TESS: Red Asymmetry of Hα Emission Associated with White-Light Emission
The frequency ratio and time delay of solar radio emissions with fundamental and harmonic components
Prospects of Detecting Non-thermal Protons in Solar Flares via Lyman Line Spectroscopy: Revisiting the Orrall-Zirker Effect
Rapid Rotation of an Erupting Prominence and the Associated Coronal Mass Ejection on 13 May 2013
Spectral and Imaging Diagnostics of Spatially-Extended Turbulent Electron Acceleration and Transport in Solar Flares
Detection of a high-velocity prominence eruption leading to a CME associated with a superflare on the RS CVn-type star V1355 Orionis
Magnetohydrodynamics Instabilities of Double Magnetic Bands in a Shallow-water Tachocline Model: I Cross-equatorial Interactions of Bands
Stability of slow magnetoacoustic and entropy waves in the solar coronal plasma with thermal misbalance
The chromosphere underneath a Coronal Bright Point

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