Magnetic flux density in the heliosphere through several solar cycles

G. Erdős, A. Balogh

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

We studied the magnetic flux density carried by solar wind to various locations in the heliosphere, covering a heliospheric distance range of 0.3-5.4 AU and a heliolatitudinal range from 80° south to 80°north. Distributions of the radial component of the magnetic field, BR, were determined over long intervals from the Helios, ACE, STEREO, and Ulysses missions, as well as from using the 1 AU OMNI data set. We show that at larger distances from the Sun, the fluctuations of the magnetic field around the average Parker field line distort the distribution of BR to such an extent that the determination of the unsigned, open solar magnetic flux density from the average 〈|BR|〉 is no longer justified. We analyze in detail two methods for reducing the effect of fluctuations. The two methods are tested using magnetic field and plasma velocity measurements in the OMNI database and in the Ulysses observations, normalized to 1 AU. It is shown that without such corrections for the fluctuations, the magnetic flux density measured by Ulysses around the aphelion phase of the orbit is significantly overestimated. However, the matching between the in-ecliptic magnetic flux density at 1 AU (OMNI data) and the off-ecliptic, more distant, normalized flux density by Ulysses is remarkably good if corrections are made for the fluctuations using either method. The main finding of the analysis is that the magnetic flux density in the heliosphere is fairly uniform, with no significant variations having been observed either in heliocentric distance or heliographic latitude.

Original languageEnglish
Article number50 (12pp)
JournalAstrophysical Journal
Volume781
Issue number1
DOIs
Publication statusPublished - 2014

Fingerprint

heliosphere
solar cycles
solar cycle
magnetic flux
flux density
ecliptic
magnetic field
Ulysses mission
magnetic fields
STEREO (observatory)
velocity measurement
solar wind
sun
coverings
intervals
orbits
plasma
method

Keywords

  • solar wind
  • Sun: activity
  • Sun: heliosphere
  • Sun: magnetic fields

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics
  • Nuclear and High Energy Physics

Cite this

Magnetic flux density in the heliosphere through several solar cycles. / Erdős, G.; Balogh, A.

In: Astrophysical Journal, Vol. 781, No. 1, 50 (12pp), 2014.

Research output: Contribution to journalArticle

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