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Correlations with Magnetic Activity in the Solar Near-Surface Shear Layer. II. Radial Shear
M. Cristina Rabello Soares, Sarbani Basu, Richard S. Bogart +1
Using Helioseismic and Magnetic Imager ring-diagram measurements and building on the rotation-rate inferences presented in Paper I for depths of 1-17 Mm, we examine the propert…
Correlations with Magnetic Activity in the Solar Near-Surface Shear Layer. I. Rotation
M. Cristina Rabello Soares, Sarbani Basu, Richard S. Bogart
We used data from the Helioseismic and Magnetic Imager to determine the rotation rate of the near-surface shear layer and its time variation. We applied the ring-diagram analysis t…
Stray Light Correction for the Helioseismic and Magnetic Imager
A. A. Norton, T. L. Duvall, J. Schou +6
We report a point spread function (PSF) and deconvolution procedure to remove stray light from the Helioseismic and Magnetic Imager (HMI) data. Pre-launch calibration observations,…
Exploring Substructure of the Near-Surface Shear Layer of the Sun
M. Cristina Rabello Soares, Sarbani Basu, Richard Bogart
The gradient of rotation in the near-surface shear layer (NSSL) of the Sun provides valuable insights into the dynamics associated with the solar activity cycle and the dynamo. Res…
Evidence of a Quasi-periodic Global-scale Oscillation in the Near-Surface Shear Layer of the Sun
Richard S. Bogart, Charles S. Baldner, Sarbani Basu +2
We present evidence of hitherto undiscovered global-scale oscillations in the near-surface shear layer of the Sun. These oscillations are seen as large scale variations of radial s…
HMI Ring Diagram Analysis: Effects of tracking, noise and resolution
Sarbani Basu, Richard S. Bogart
Ring diagram analysis is a standard local helioseismic technique. Data from the Helioseismic and Magnetic Imager (HMI) on the Solar Dynamics Observatory (SDO) are routinely used fo…
Solar inertial modes: Observations, identification, and diagnostic promise
Laurent Gizon, Robert H. Cameron, Yuto Bekki +10
The oscillations of a slowly rotating star have long been classified into spheroidal and toroidal modes. The spheroidal modes include the well-known 5-min acoustic modes used in he…
Exploring the latitude and depth dependence of solar Rossby waves using ring-diagram analysis
B. Proxauf, L. Gizon, B. Löptien +3
Global-scale Rossby waves have recently been unambiguously identified on the Sun. Here we study the latitude and depth dependence of the Rossby wave eigenfunctions. By applying hel…
Global-scale equatorial Rossby waves as an essential component of solar internal dynamics
Björn Löptien, Laurent Gizon, Aaron C. Birch +5
The Sun's complex dynamics is controlled by buoyancy and rotation in the convection zone and by magnetic forces in the atmosphere and corona. While small-scale solar convection is…
Statistical analysis of acoustic wave power and flows around solar active regions
M. Cristina Rabello-Soares, Richard S. Bogart, Philip H. Scherrer
We analyze the effect of a sunspot in its quiet surroundings applying a helioseismic technique on almost three years of Helioseismic and Magnetic Imager (HMI) observations obtained…
Statistical analysis of acoustic wave parameters near active regions
M. Cristina Rabello Soares, Richard S. Bogart, Philip H. Scherrer
In order to quantify the influence of magnetic fields on acoustic mode parameters and flows in and around active regions, we analyse the differences in the parameters in magnetical…
Observables Processing for the Helioseismic and Magnetic Imager Instrument on the Solar Dynamics Observatory
Sebastien Couvidat, Jesper Schou, J. Todd Hoeksema +6
NASA's Solar Dynamics Observatory (SDO) was launched 11 February 2010 with 3 instruments on board, including the Helioseismic and Magnetic Imager (HMI). Since beginning normal oper…
Evolution of Near-surface Flows Inferred from High-resolution Ring-diagram Analysis
Richard S. Bogart, Charles S, . Baldner +1
Ring-diagram analysis of acoustic waves observed at the photosphere can provide a relatively robust determination of the sub-surface flows at a particular time under a particular r…
Chromospheric and Coronal Observations of Solar Flares with the Helioseismic and Magnetic Imager
Juan-Carlos Martínez Oliveros, Säm Krucker, Hugh S. Hudson +7
We report observations of white-light ejecta in the low corona, for two X-class flares on the 2013 May 13, using data from the Helioseismic and Magnetic Imager (HMI) of the Solar D…
Detection of Equatorward Meridional Flow and Evidence of Double-Cell Meridional Circulation inside the Sun
Junwei Zhao, R. S. Bogart, A. G. Kosovichev +2
Meridional flow in the solar interior plays an important role in redistributing angular momentum and transporting magnetic flux inside the Sun. Although it has long been recognized…
Temporal Variations of High-Degree Solar p-Modes using Ring-Diagram Analysis
Olga Burtseva, Sushant Tripathy, Richard Bogart +4
We study temporal variations in the amplitudes and widths of high-degree acoustic modes by applying the ring-diagram technique to the GONG+, MDI and HMI Dopplergrams during the dec…
Two-Dimensional Helioseismic Power, Phase, and Coherence Spectra of {\it Solar Dynamics Observatory} Photospheric and Chromospheric Observables
Rachel Howe, Kiran Jain, Richard S. Bogart +2
While the {\it Helioseismic and Magnetic Imager} (HMI) onboard the {\it Solar Dynamics Observatory} (SDO) provides Doppler velocity [], continuum intensity [], and line-dep…
Systematic Center-to-Limb Variation in Measured Helioseismic Travel Times and Its Effect on Inferences of Solar Interior Meridional Flows
Junwei Zhao, Kaori Nagashima, R. S. Bogart +2
We report on a systematic center-to-limb variation in measured helioseismic travel times, which must be taken into account for an accurate determination of solar interior meridiona…
Evidence for solar frequency dependence on sunspot type
Charles S. Baldner, Richard S. Bogart, Sarbani Basu
High degree solar mode frequencies as measured by ring diagrams are known to change in the presence of the strong magnetic fields found in active regions. We examine these changes…
Time--Distance Helioseismology Data Analysis Pipeline for Helioseismic and Magnetic Imager onboard Solar Dynamics Observatory (SDO/HMI) and Its Initial Results
J. Zhao, S. Couvidat, R. S. Bogart +6
The Helioseismic and Magnetic Imager onboard the Solar Dynamics Observatory (SDO/HMI) provides continuous full-disk observations of solar oscillations. We develop a data-analysis p…
Temporal Variations of High-Degree Solar p-Modes from GONG and MDI
Olga Burtseva, S. C. Tripathy, R. Howe +4
We study temporal variations in the amplitudes and widths of high-degree acoustic modes in the quiet and active Sun by applying ring-diagram technique to the GONG+ and MDI Dopplerg…
Local helioseismology of sunspot regions: comparison of ring-diagram and time-distance results
A. G. Kosovichev, S. Basu, R. Bogart +10
Local helioseismology provides unique information about the subsurface structure and dynamics of sunspots and active regions. However, because of complexity of sunspot regions loca…
Helioseismology of Sunspots: A Case Study of NOAA Region 9787
L. Gizon, H. Schunker, C. S. Baldner +12
Various methods of helioseismology are used to study the subsurface properties of the sunspot in NOAA Active Region 9787. This sunspot was chosen because it is axisymmetric, shows…