English
 
User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  Solar Cycle Occurrence of Alfvénic Fluctuations and Related Geo-Efficiency

Tanskanen, E., Snekvik, K., Slavin, J., Pérez-Suárez, D., Viljanen, A., Goldstein, M., et al. (2017). Solar Cycle Occurrence of Alfvénic Fluctuations and Related Geo-Efficiency. Journal of Geophysical Research: Space Physics, 122(10), 9848-9857. doi:10.1002/2017JA024385.

Item is

Basic

show hide
Item Permalink: http://hdl.handle.net/21.11116/0000-0001-1AF1-2 Version Permalink: http://hdl.handle.net/21.11116/0000-0001-5B0E-B
Genre: Journal Article

Files

show Files

Locators

show

Creators

show
hide
 Creators:
Tanskanen, E.I., Author
Snekvik, K., Author
Slavin, J.A., Author
Pérez-Suárez, D., Author
Viljanen, A., Author
Goldstein, M., Author
Käpylä, Maarit J.1, 2, Author              
Hynönen, R., Author
Häkkinen, L.V.T., Author
Mursula, K., Author
Affiliations:
1Department Sun and Heliosphere, Max Planck Institute for Solar System Research, Max Planck Society, ou_1832289              
2Max Planck Research Group in Solar and Stellar Magnetic Activity, Max Planck Institute for Solar System Research, Max Planck Society, Justus-von-Liebig-Weg 3, 37077 Göttingen, DE, ou_2265638              

Content

show
hide
Free keywords: -
 MPIS_GROUPS: Research Group Solar Stellar Mag Activity
 Abstract: We examine solar wind intervals with Alfvénic fluctuations (ALFs) in 1995–2011. The annual number, the total annual duration, and the average length of ALFs vary over the solar cycle, having a maximum in 2003 and a minimum in 2009. ALFs are most frequent in the declining phase of solar cycle, when the number of high-speed streams at the Earth's vicinity is increased. There is a rapid transition after the maximum of solar cycle 23 from ALFs being mainly embedded in slow solar wind (<400 km/s) until 2002 to ALFs being dominantly in fast solar wind (>600 km/s) since 2003. Cross helicity increased by 30% from 2002 to 2003 and maximized typically 4–6 h before solar wind speed maximum. Cross helicity remained elevated for several days for highly Alfvénic non-ICME streams, but only for a few hours for ICMEs. The number of substorms increased by about 40% from 2002 to 2003, and the annual number of substorms closely follows the annual cross helicity. This further emphasizes the role of Alfvénic fluctuations in modulating substorm activity. The predictability of substorm frequency and size would be greatly improved by monitoring solar wind Alfvénic fluctuations in addition to the mean values of the important solar wind parameters.

Details

show
hide
Language(s): eng - English
 Dates: 2018-04-102017
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: DOI: 10.1002/2017JA024385
 Degree: -

Event

show

Legal Case

show

Project information

show

Source 1

show
hide
Title: Journal of Geophysical Research: Space Physics
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: Washington, D.C. : American Geophysical Union
Pages: - Volume / Issue: 122 (10) Sequence Number: - Start / End Page: 9848 - 9857 Identifier: ISSN: 0148-0227
CoNE: https://pure.mpg.de/cone/journals/resource/991042728714264