Category Archives: Magnetic Field

92. Photospheric Magnetic Properties of Active Regions: Br or Blos?

Contributed by Jordan A. Guerra Aguilera. Posted on March 26, 2018

The majority of flare forecasting methods rely on observations of magnetic field on the Sun’s surface, but which observable, Br or Blos, is a better predictor? Through comparing a few magnetic properties derived from both observables, this nugget gives some suggestion.

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.

87. Magnetic Reconnection at the Earliest Stage of Solar Flux Emergence

Contributed by Hui Tian. Posted on March 1, 2018

The early phase of a flux emergence was observed by IRIS, and spectra of the accompanying UV bursts are analyzed. Many bursts appear to be associated with the magnetic flux cancellation, and almost all of them are located in regions with large squashing factors.

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.

79. Homologous Circular-Ribbon Flares Driven by Twisted Flux Emergence

Contributed by Zhi Xu. Posted on December 18, 2017

Two homologous circular-ribbon flares associated with two filament eruptions were observed and analyzed. The emergence of magnetic flux ropes helped to inject free energy into the region and drive the magnetic reconnection above it.