Author Archives: admin
70. Magnetic Flux Emergence & Decay Rates for Sunspots Observed with HMI
We quantify the emergence and decay rates of ten bipolar active regions using vector magnetic field data from HMI. Our results, placed in context with other observational and modeling results in the literature, confirm a trend that higher flux regions emerge faster and the rate is dependent on the total flux of that region.
69. Measuring Differential Rotation and Meridional Circulation by Direct Tracking of Photospheric Magnetic Features
68. Magnetic Field Changes in the Photosphere and the Chromosphere During the X1 Flare on 2014-03-29
67. The New HMI High-Cadence Vector Magnetograms
66. A Poynting-Robertson-Like Drag at the Sun’s Surface
A new analysis using about 4 years of HMI 5-min solar p-mode limb oscillations as a rotation “tracer” finds a large velocity gradient at the top of the photosphere. It is suggested that the net effect of the photospheric angular momentum loss is similar to Poynting-Robertson “photon braking” on, for example, Sun-orbiting dust.
65. SDO Reveals the Properties of Flare-productive Sunspot Regions
64. Slow Appearance of Sunspots Challenges Theory
63. A New Python Module for Accessing HMI and AIA Data
62. Tracing p-Mode Waves from the Photosphere to the Corona in Active Regions
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.