Tag Archives: active regions

99. A Comparative Study between A Failed and A Successful Eruption Initiated from the Same Polarity Inversion Line in AR 11387

Contributed by Lijuan Liu. Posted on May 22, 2018

Two flares occurred in a same active region above a same polarity inversion line, but one had a failed CME eruption but another one had a successful CME eruption. This study explored why that was the case.

96. Evaluation of Applicability of a Flare Trigger Model
 Based on a Comparison of Geometric Structures


Contributed by Yumi Bamba. Posted on April 23, 2018

A sample of 32 flare events are analyzed to evaluate how these events agree with a flare-triggering model, which examines shear angles of large-scale magnetic field and small-scale dipole field during the flares’ precursor brightening.

93. Formation of Penumbra in A Sample of Active Regions Observed by the SDO Satellite

Contributed by Mariarita Murabito. Posted on March 29, 2018

Where does a sunspot’s penumbra start to form, on the same side or the opposite side of its opposite-polarity sunspot? When does Evershed flow start to appear, before or after the penumbral formation? These questions are answered through analyzing selected samples observed by the HMI.

90. A Comparative Study of the Eruptive and Non-Eruptive Flares Produced by the Largest Active Region of Solar Cycle 24

Contributed by Ranadeep Sarkar. Posted on March 18, 2018

AR12192, the largest active region in Solar Cycle 24, produced 6 X-class flares, but none of them were associated with a CME. However, a much weaker flare, of M4.0-class, was associated with a CME. Magnetic field and morphological changes are analyzed during these flares to understand why this is the case.

84. Abrupt and Permanent Changes of the Photospheric Magnetic Field During 75 flares observed with HMI

Contributed by Sebastián Castellanos Durán. Posted on January 16, 2018

Magnetic field changes associated with solar flares, observed by the SDO/HMI, are surveyed, and permanent changes of magnetic field are found in the majority of flare events. Properties of the magnetic field changes are further investigated.

62. Tracing p-Mode Waves from the Photosphere to the Corona in Active Regions

Contributed by Junwei Zhao. Posted on October 30, 2016

Through analyzing a suite of space- and ground-based observations, the authors report that above sunspots, helioseismic waves of different frequencies are able to channel up through the chromosphere and transition region into corona. General pictures of how the waves make into corona are also shown.

60. SDO/HMI Survey of Emerging Active Regions for Helioseismology and Other Solar Physics Applications (SDO/HEAR)

Contributed by Hannah Schunker. Posted on September 28, 2016

We have generated a dataset of emerging active regions (EARs) observed by SDO/HMI that is specifically suitable for helioseismic analysis. Using this dataset we show that, on average the bipoles have a symmetric the east-west velocity relative to differential rotation.

51. Magnetic Field Reconstruction Based on Sunspot Oscillations

Contributed by Johannes Löhner-Böttcher. Posted on April 25, 2016

We observed magnetoacoustic waves propagating along the magnetic field lines of a sunspot. Based on the wave periods and atmospheric characteristics, we reconstructed the magnetic field topology of the sunspot.