Solar Sector Structure

Abstract

The interplanetary magnetic field near has a characteristic "sector" structure that reflects its polarity relative to the solar direction. Typically we observe large-scale coherence in these directions, with two or four "away" or "towards" sectors per solar rotation, from any platform in deep space and near the ecliptic plane. In a simple picture, this morphology simply reflects the idea that the sources of the interplanetary field lie mainly in or near the Sun, and that the solar-wind flow enforces a radial component in this field. Although defined strictly via the interplanetary field near one AU, recent evidence confirms that this pattern also appears clearly at the level of the photosphere, with signatures including not only the large-scale structures (e.g., the streamers) but also highly concentrated fields such as those found in sunspots and even solar flares. This association with small-scale fields strengthens at the Hale sector boundary, defining the Hale boundary as the one for which the polarity switch matches that of the leading-to-following polarity alternation in the sunspots of a given hemisphere.

References in corpus (10)

• A Critical Assessment of Nonlinear Force-Free Field Modeling of the Solar Corona for Active Region 10953
• A Model for the Sources of the Slow Solar Wind
• Different Power-law Indices in the Frequency Distributions of Flares with and without Coronal Mass Ejections
• The Sun's Global Photospheric and Coronal Magnetic Fields: Observations and Models
• Magnetic Structure of Sunspots
• Structure and Dynamics of the Sun's Open Magnetic Field
• Coronal Magnetic Field Evolution from 1996 to 2012: Continuous Non-Potential Simulations
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• Nonlinear Force-Free Magnetic Field Fitting to Coronal Loops with and without Stereoscopy
• Flaring Solar Hale Sector Boundaries

Cited by in corpus (6)

• Solar cycle indices from the photosphere to the corona: measurements and underlying physics
• On the variability of the solar mean magnetic field: contributions from various magnetic features on the surface of the Sun
• Influence of Non-Potential Coronal Magnetic Topology on Solar-Wind Models
• The association of the Hale Sector Boundary with RHESSI solar flares and active longitudes
• Two Types of $1/f$ Range in Solar Wind Turbulence
• Solar Mean Magnetic Field of the Chromosphere