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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…
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…
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 …
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…
High-resolution Imaging of Solar Flare Ribbons and Its Implication on the Thick-target Beam Model
Krucker, Säm; Lin, R. P.; Hudson, H. S. +5 more
We report on high-resolution optical and hard X-ray observations of solar flare ribbons seen during the GOES X6.5 class white-light flare of 2006 December 6. The data consist of imaging observations at 430 nm (the Fraunhofer G band) taken by the Hinode Solar Optical Telescope with the hard X-rays observed by the Reuven Ramaty High Energy Solar Spe…
Using a Differential Emission Measure and Density Measurements in an Active Region Core to Test a Steady Heating Model
Winebarger, Amy R.; Warren, Harry P.; Kashyap, Vinay L. +2 more
The frequency of heating events in the corona is an important constraint on the coronal heating mechanisms. Observations indicate that the intensities and velocities measured in active region cores are effectively steady, suggesting that heating events occur rapidly enough to keep high-temperature active region loops close to equilibrium. In this …
The First Measurement of the Adiabatic Index in the Solar Corona Using Time-dependent Spectroscopy of Hinode/EIS Observations
Del Zanna, Giulio; Van Doorsselaere, Tom; Nakariakov, Valery M. +3 more
We use observations of a slow magnetohydrodynamic wave in the corona to determine for the first time the value of the effective adiabatic index, using data from the Extreme-ultraviolet Imaging Spectrometer on board Hinode. We detect oscillations in the electron density, using the CHIANTI atomic database to perform spectroscopy. From the time-depen…
Two Components of the Solar Coronal Emission Revealed by Extreme-ultraviolet Spectroscopic Observations
Martínez-Sykora, Juan; De Pontieu, Bart; Wang, Xin +3 more
Recent spectroscopic observations have revealed the ubiquitous presence of blueward asymmetries of emission lines formed in the solar corona and transition region. These asymmetries are most prominent in loop footpoint regions, where a clear correlation of the asymmetry with the Doppler shift and line width determined from the single-Gaussian fit …
Constraints on the Heating of High-temperature Active Region Loops: Observations from Hinode and the Solar Dynamics Observatory
Winebarger, Amy R.; Warren, Harry P.; Brooks, David H.
We present observations of high-temperature emission in the core of a solar active region using instruments on Hinode and the Solar Dynamics Observatory (SDO). These multi-instrument observations allow us to determine the distribution of plasma temperatures and follow the evolution of emission at different temperatures. We find that at the apex of…
Atmospheric Imaging Assembly Observations of Hot Flare Plasma
Reeves, Katharine K.; Golub, Leon
We present observations of hot plasma from solar eruptions recorded by the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory. AIA is the first narrowband instrument capable of taking images of hot plasma in the 5-15 MK range. We find that there are hot structures above flare loops, and that they are typically more diffuse and ne…