Contributed by Chia-Hsien Lin. Posted on August 17, 2022
This study reveals that a significant number of coronal-hole field lines extend beyond the coronal-hole boundaries and that many coronal-holes contain no open magnetic field lines.
Contributed by Avijeet Prasad. Posted on July 29, 2022
Inverse Evershed flow is derived from chromospheric observations. Coupling these flow with the non force-free model, the authors find that the flow is driven along magnetic field lines connecting network elements with the outer penumbra by a gas pressure difference.
Contributed by Keiji Hayashi. Posted on May 30, 2022
Briefly shown here are some results from a new global coronal MHD simulation model, with a new method to use the three-component vector HMI synoptic maps as time-dependent boundary values.
Contributed by Evangelia Liokati. Posted on March 30, 2022
A statistical study of emerging active regions demonstrates that these ARs tend to produce CMEs when they accumulate significant budgets of both magnetic helicity and energy.
Contributed by Yang Liu. Posted on March 22, 2022
The authors show that the new inversion code for the HMI’s vector field reduces the number of pixels that reverse signs after passing the central meridian. The analysis also reveals that the radial components of the HMI’s vector magnetic fields have a hemispheric bias, too.
Contributed by Ana Griñón-Marín. Posted on March 21, 2022
For weak magnetic regions, HMI’s vector magnetic fields are known to give ambiguous signs in the east-west direction. A new inversion strategy is developed to address this problem, and the follow-up analysis shows that the new code improves HMI’s weak vector magnetic fields.
Contributed by Maria Kazachenko. Posted on February 24, 2022
Through analyzing a number of active regions, this analysis finds that while flares are guided by the physical properties that scale with AR size, CMEs are guided by mean properties, with little dependence on the amount of shear at the polarity inversion line or the net current.
Contributed by Rui Wang. Posted on February 17, 2022
This analysis shows that a new bipolar emergence, whose positive polarity collided with the pre-existing negative polarity, in AR11283 led to energy and helicity buildup in the form of magnetic flux ropes. Recurrent energy releases caused a few homologous CMEs from this region.
Contributed by Jonathan Lee. Posted on February 16, 2022
A segment of bald patch in AR 12673 disintegrated rapidly during solar cycle 24’s most intense flare. The horizontal magnetic field perpendicular to the polarity inversion line changed sign, while the parallel component permanently increased.
Contributed by Aimee Norton. Posted on October 29, 2021
In order to make the properties of magnetic features observed by SDO/HMI more accessible, the Solar Photospheric Ephemeral and Active Region (SPEAR) catalogue has been created as an easy-to-read tabulated text file. Tilt angles from the SPEAR catalogue are shown as a histogram (top) and as a function of latitude (bottom) with colors indicating all regions (blue), regions with anti-Joy (red), and anti-Hale (purple) tilts. Over 40% of regions disobey the laws of Joy and Hale.