Tag Archives: magnetic field

159. Magnetic Field Dependence of Bipolar Magnetic Region Tilts on the Sun: Indication of Tilt Quenching

Contributed by Bibhuti Kumar Jha. Posted on June 15, 2021

Magnetic-field dependence of active regions’ tilt angles are analyzed using the MDI and HMI observations for two solar cycles. The variation of the tilt angles with the maximum magnetic-field strength of the ARs indicates a nonlinear tilt quenching in the Babcock–Leighton process.

156. Fast and Accurate Emulation of the SDO/HMI Stokes Inversion with Uncertainty Quantification

Contributed by Richard Higgins. Posted on April 16, 2021

An emulation of the VFISV Stokes Inversion that trains a deep
network (U-Net) to map directly from IQUV polarized light to Milne-Eddington magnetic field parameters. The accuracy of this method suggests that it could serve as a warm-start for VFISV or as a pre-disambiguation stand-in.

149. Activity Complexes and a Prominent Poleward Surge During Solar Cycle 24

Contributed by Zi-Fan Wang. Posted on December 15, 2020

A surface flux-transport dynamo model assimilation shows that the long-lasting active-region complexes, which appeared in the Sun’s southern hemisphere during Cycle 24, played a crucial role in the pole’s polarity reversal and the field strength at the cycle minimum.

147. Recurring Homologous Solar Eruptions in NOAA AR 11429

Contributed by Suman Dhakal. Posted on October 14, 2020

Through studying three homologous eruptive events in an active region, the authors conclude that shearing motions and magnetic flux cancellation play a dominant role leading to the recurrent eruptions, and are key processes forming the eruptive structures.

144. Finding the critical decay index in solar prominence eruptions

Contributed by Vemareddy Panditi. Posted on September 1, 2020

Critical decay index is a measure of the rate at which background field intensity decreases with height over the flux ropes or erupting structures. The indices for 10 eruptive prominences are calculated, and their relations to the eruptions are discussed.