205. Is the solar meridional circulation profile single-, double-, or multiple-cell?

Contributed by Yoshiki Hatta. Posted on October 22, 2024

Is the solar meridional circulation profile single-, double-, or multiple-cell? At least, a constraint of equatorward angular momentum transport by meridional circulation favors the double-cell structure, although the inversion with a constraint of mass conservation favors single cell.

204. Exploring Meridional Flow in the Solar Polar Caps

Contributed by Shuhong Yang. Posted on October 14, 2024

A surface flux transport model, using HMI-observed global magnetic field and active regions as inputs, with different polar meridional-flow profiles simulates the magnetic field in the polar caps. The simulation is then compared with Hinode-observed polar magnetic fields. The result supports an existence of counter cells above 70-degree latitude in each hemisphere.

203. Exploring Substructure of the Near-Surface Shear Layer of the Sun

Contributed by Cristina Rabello Soares. Posted on October 4, 2024

The Sun’s near surface shear layer (NSSL) is characterized by using HMI ring-diagram results. It is found the NSSL is composed of three distinct layers: a deeper larger region with a small shear, a narrow middle layer with a strong shear, and a layer very close to the surface.

202. Optimization of Solar White-Light Flare Identification Methods and Its Application

Contributed by Yijun Hou. Posted on September 24, 2024

A new method was developed to identify white-light flares (WLFs) observed in SDO/HMI continuum intensity. The new method is able to identify around 30% of C-class flares (and more percentage in stronger flares) having white light brightening associated with them, greatly expanding the total number of WLFs observed by HMI. The increased number of detections would help a statistical study of the properties of WLFs.

201. Study of Bipolar Magnetic Regions using AutoTAB: Support of Thin Flux Tube Model?

Contributed by Bidya Karak. Posted on July 4, 2024

This study analyzes a few properties of evolving bipolar magnetic regions: separation of polarities, tilt angles, and tilt angle and flux relations. The analysis supports that the bipolar regions form from thin-flux tubes and Coriolis force plays an important role in forming the regions.

198. Spectro-Polarimetric Properties of Sunquake Sources and the Origin of Sunquakes

Contributed by A. G. Kosovichev. Posted on February 13, 2024

A spectro-polarimetric analysis of the sunquake sources observed during an X1.5 flare revealed transient emission in the FeI 6173Å line core, indicating intense, impulsive heating in the lower photosphere at the beginning of the flare impulsive phase.

196. Observations of Rossby wave parameter variations during solar cycle 24

Contributed by Mattias Waidele. Posted on September 25, 2023

Equatorial Rossby waves are detected using the HMI’s time-distance subsurface flow fields. It is also found that the power of the Rossby waves show a positive correlation with the sunspot number, while the frequency of the waves shows an anti-correlation with the sunspot number.