Tag Archives: sunspot oscillations

152. Probing the Solar Meridional Circulation using Fourier Legendre Decomposition

Contributed by Doug Braun. Posted on March 16, 2021

Fourier Legendre decomposition is applied on HMI’s long-term Doppler-velocity observations to derive the Sun’s internal meridional circulation. In addition to the well-known center-to-limb effect, a non-axisymmetric component in the northern- and southern-hemisphere is identified as another systematic effect that complicates the derivation of the internal meridional circulation.

150. Photospheric Oscillations in and around Active Region 11158, including the Polarity Inversion Line

Contributed by Aimee Norton. Posted on January 20, 2021

To search for signatures of Alfvénic waves in the solar photosphere, the authors analyze the oscillation amplitudes, phases and time-distance behavior between different observables in a sunspot umbra, its polarity inversion line, and surrounding area.

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.