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Heating of the Solar Chromosphere and Corona by Alfvén Wave Turbulence
Cranmer, S. R.; van Ballegooijen, A. A.; DeLuca, E. E. +1 more
A three-dimensional magnetohydrodynamic (MHD) model for the propagation and dissipation of Alfvén waves in a coronal loop is developed. The model includes the lower atmospheres at the two ends of the loop. The waves originate on small spatial scales (less than 100 km) inside the kilogauss flux elements in the photosphere. The model describes the n…
The Origins of Hot Plasma in the Solar Corona
Schrijver, C. J.; De Pontieu, B.; Tarbell, T. D. +6 more
The Sun's outer atmosphere, or corona, is heated to millions of degrees, considerably hotter than its surface or photosphere. Explanations for this enigma typically invoke the deposition in the corona of nonthermal energy generated by magnetoconvection. However, the coronal heating mechanism remains unknown. We used observations from the Solar Dyn…
VFISV: Very Fast Inversion of the Stokes Vector for the Helioseismic and Magnetic Imager
Schou, J.; Kubo, M.; Borrero, J. M. +4 more
In this paper we describe in detail the implementation and main properties of a new inversion code for the polarized radiative transfer equation (VFISV: Very Fast Inversion of the Stokes Vector). VFISV will routinely analyze pipeline data from the Helioseismic and Magnetic Imager (HMI) on-board of the Solar Dynamics Observatory (SDO). It will prov…
Photospheric flux cancellation and associated flux rope formation and eruption
Green, L. M.; Kliem, B.; Wallace, A. J.
Aims: We study an evolving bipolar active region that exhibits flux cancellation at the internal polarity inversion line, the formation of a soft X-ray sigmoid along the inversion line and a coronal mass ejection. The aim is to investigate the quantity of flux cancellation that is involved in flux rope formation in the time period leading up …
Propagating Waves Along Spicules
De Pontieu, Bart; Okamoto, Takenori J.
Alfvénic waves are thought to play an important role in coronal heating and acceleration of solar wind. Here we investigate the statistical properties of Alfvénic waves along spicules (jets that protrude into the corona) in a polar coronal hole using high-cadence observations of the Solar Optical Telescope on board Hinode. We developed a technique…
Magnetic Structure of Sunspots
Ichimoto, Kiyoshi; Borrero, Juan M.
In this review we give an overview about the current state-of-knowledge of the magnetic field in sunspots from an observational point of view. We start by offering a brief description of tools that are most commonly employed to infer the magnetic field in the solar atmosphere with emphasis in the photosphere of sunspots. We then address separately…
Magneto-thermal convection in solar prominences
Shibata, Kazunari; Testa, Paola; Boerner, Paul +6 more
Coronal cavities are large low-density regions formed by hemispheric-scale magnetic flux ropes suspended in the Sun's outer atmosphere. They evolve over time, eventually erupting as the dark cores of coronal mass ejections. Although coronal mass ejections are common and can significantly affect planetary magnetospheres, the mechanisms by which cav…
Establishing a Connection Between Active Region Outflows and the Solar Wind: Abundance Measurements with EIS/Hinode
Warren, Harry P.; Brooks, David H.
One of the most interesting discoveries from Hinode is the presence of persistent high-temperature high-speed outflows from the edges of active regions (ARs). EUV imaging spectrometer (EIS) measurements indicate that the outflows reach velocities of 50 km s-1 with spectral line asymmetries approaching 200 km s-1. It has been …
SDO AIA and Hinode EIS observations of "warm" loops
Mason, H. E.; Del Zanna, G.; O'Dwyer, B.
We present simultaneous observations of active region "warm" (1 MK) loops using the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) and Hinode EUV Imaging Spectrometer (EIS). Sample EIS spectra for a loop footpoint and a lop leg region are presented, and are used to describe the spectral lines which contribute to the six AIA EU…
Observations and Magnetic Field Modeling of the Flare/coronal Mass Ejection Event on 2010 April 8
Golub, Leon; van Ballegooijen, Adriaan; DeLuca, Edward +2 more
We present a study of the flare/coronal mass ejection event that occurred in Active Region 11060 on 2010 April 8. This event also involves a filament eruption, EIT wave, and coronal dimming. Prior to the flare onset and filament eruption, both SDO/AIA and STEREO/EUVI observe a nearly horizontal filament ejection along the internal polarity inversi…