Imperial College London
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ProfessorTimothyHorbury

Faculty of Natural Sciences, Department of Physics

Professor of Physics
 
 
 
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Contact

 

+44 (0)20 7594 7676t.horbury Website

 
 
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Location

 

6M65Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Stansby:2018:0004-6361/201732567,
author = {Stansby, D and Horbury, T},
doi = {0004-6361/201732567},
journal = {Astronomy and Astrophysics},
title = {Number density structures in the inner heliosphere},
url = {http://dx.doi.org/10.1051/0004-6361/201732567},
volume = {613},
year = {2018}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Aims.The origins and generation mechanisms of the slow solar wind are still unclear. Part of the slow solar wind is populated by“number density structures”, discrete patches of increased number density that are frozen in to and move with the bulk solar wind. Inthis paper we aimed to provide the first in-situ statistical study of number density structures in the inner heliosphere.Methods.We reprocessed in-situ ion distribution functions measured by Helios in the inner heliosphere to provide a new reliable setof proton plasma moments for the entire mission. From this new data set we looked for number density structures measured within0.5 AU of the Sun and studied their properties.Results.We identified 140 discrete areas of enhanced number density. The structures occurred exclusively in the slow solar wind andspanned a wide range of length scales from 50 Mm to 2000 Mm, which includes smaller scales than have been previously observed.They were also consistently denser and hotter that the surrounding plasma, but had lower magnetic field strengths, and thereforeremained in pressure balance.Conclusions.Our observations show that these structures are present in the slow solar wind at a wide range of scales, some of whichare too small to be detected by remote sensing instruments. These structures are rare, accounting for only 1% of the slow solar windmeasured by Helios, and are not a significant contribution to the mass flux of the solar wind.
AU  - Stansby,D
AU  - Horbury,T
DO  - 0004-6361/201732567
PY  - 2018///
SN  - 0004-6361
TI  - Number density structures in the inner heliosphere
T2  - Astronomy and Astrophysics
UR  - http://dx.doi.org/10.1051/0004-6361/201732567
UR  - http://hdl.handle.net/10044/1/58397
VL  - 613
ER  -
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