Over 63% of solar active region flux in Cycle 24 clusters in three bands whose drift rates match phase speeds of slow magneto-Rossby waves with toroidal field ~4 kG.
Moderate Nesting and Cross-Equatorial Asymmetry of Active Regions in Solar Cycle 24
1 Pith paper cite this work. Polarity classification is still indexing.
abstract
Solar Cycle 24 data are used to determine how often the Sun emerges sunspots in `activity nests', i.e., regions where sunspots and active regions (ARs) repeatedly emerge. We use the Solar Photospheric Ephemeral Active Region (SPEAR) catalog created from Helioseismic and Magnetic Imager (HMI) data as well as the HMI Carrington Rotation maps of radial magnetic field, $B_r$. The Sun shows moderate nesting behavior with 41\% (48\%) of AR magnetic flux found in Northern (Southern) hemispheric nests that are short-lived (average lifetimes $\sim$3.3 - 4.0 months). Different rotation rates are used to search for nests that may not be evident `by eye'. The maximum number of nests are found with slightly prograde rotational velocities, with significant nest flux also found at synodic 451--452 nHz prograde and 409--411 nHz retrograde frequencies. Nest patterns show strong hemispheric asymmetry, indicating that the physical origin of nests identified herein must also be asymmetric or antisymmetric across the equator.
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astro-ph.SR 1years
2026 1verdicts
UNVERDICTED 1representative citing papers
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Long-Term Clustering Pattern of Solar Active Regions and Their Potential Connection with Magneto-Rossby Waves
Over 63% of solar active region flux in Cycle 24 clusters in three bands whose drift rates match phase speeds of slow magneto-Rossby waves with toroidal field ~4 kG.