On the Fluctuating Component of the Sun's Large-Scale Magnetic Field

Details On the Fluctuating Component of the Sun's Large-Scale Magnetic Field On the Fluctuating Component of the Sun's Large-Scale Magnetic Field

Jun 2003

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003apj...590.1111w&link_type=abstract

The Astrophysical Journal, Volume 590, Issue 2, pp. 1111-1120.

Astronomy and Astrophysics

Astronomy

33

Interplanetary Medium, Sun: Solar-Terrestrial Relations, Sun: Activity, Sun: Corona, Sun: Magnetic Fields, Sun: Photosphere

Scientific paper

The Sun's large-scale magnetic field and its proxies are known to undergo substantial variations on timescales much less than a solar cycle but longer than a rotation period. Examples of such variations include the double activity maximum inferred by Gnevyshev, the large peaks in the interplanetary field strength observed in 1982 and 1991, and the 1.3-1.4 yr periodicities detected over limited time intervals in solar wind speed and geomagnetic activity. We consider the question of the extent to which these variations are stochastic in nature. For this purpose, we simulate the evolution of the Sun's equatorial dipole strength and total open flux under the assumption that the active region sources (BMRs) are distributed randomly in longitude. The results are then interpreted with the help of a simple random walk model including dissipation. We find that the equatorial dipole and open flux generally exhibit multiple peaks during each 11 yr cycle, with the highest peak as likely to occur during the declining phase as at sunspot maximum. The widths of the peaks are determined by the timescale τ~1 yr for the equatorial dipole to decay through the combined action of meridional flow, differential rotation, and supergranular diffusion. The amplitudes of the fluctuations depend on the strengths and longitudinal phase relations of the BMRs, as well as on the relative rates of flux emergence and decay. We conclude that stochastic processes provide a viable explanation for the ``Gnevyshev gaps'' and for the existence of quasi periodicities in the range ~1-3 yr.

Affiliated with

Also associated with

No associations

Rating

On the Fluctuating Component of the Sun's Large-Scale Magnetic Field does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with On the Fluctuating Component of the Sun's Large-Scale Magnetic Field, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and On the Fluctuating Component of the Sun's Large-Scale Magnetic Field will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1820683