E-Print Archive

There are 4036 abstracts currently viewable.


Search:

Advanced Search
Options
Main Page Add New E-Print Submitter
Information
Feedback
News Help/FAQ About Preferences
Manage Key Phrase
Notification
Cool transition region loops observed by the Interface Region Imaging Spectrograph View all abstracts by submitter

Zhenghua Huang   Submitted: 2015-07-29 09:46

We report on the first Interface Region Imaging Spectrograph (IRIS) study of cool transition region loops. This class of loops has received little attention in the literature. A cluster of such loops was observed on the solar disk in active region NOAA11934, in the Si IV 1402.8 ? spectral raster and 1400 Å slit-jaw (SJ) images. We divide the loops into three groups and study their dynamics and interaction. The first group comprises relatively stable loops, with 382-626 km cross-sections. Observed Doppler velocities are suggestive of siphon flows, gradually changing from -10 km s-1 at one end to 20 km s-1 at the other end of the loops. Nonthermal velocities from 15 to 25 km s-1 were determined. These physical properties suggest that these loops are impulsively heated by magnetic reconnection occurring at the blue-shifted footpoints where magnetic cancellation with a rate of 1015 Mx/s is found. The released magnetic energy is redistributed by the siphon flows. The second group corresponds to two footpoints rooted in mixed-magnetic-polarity regions, where magnetic cancellation occurred at a rate of 1015 Mx/s and line profiles with enhanced wings of up to 200 km s-1 were observed. These are suggestive of explosive-like events. The Doppler velocities combined with the SJ images suggest possible anti-parallel flows in finer loop strands. In the third group, interaction between two cool loop systems is observed. Evidence for magnetic reconnection between the two loop systems is reflected in the line profiles of explosive events, and a magnetic cancellation rate of 3x1015 Mx/s observed in the corresponding area. The IRIS observations have thus opened a new window of opportunity for in-depth investigations of cool transition region loops. Further numerical experiments are crucial for understanding their physics and their role in the coronal heating processes.

Authors: Zhenghua Huang, Lidong Xia, Bo Li, Maria Madjarska
Projects: IRIS

Publication Status: ApJ (accepted)
Last Modified: 2015-07-29 13:00
Go to main E-Print page  Study of Cosmic-Ray Modulation during the Recent Unusual Minimum and Mini Maximum of Solar Cycle 24  On the speed and acceleration of electron beams triggering interplanetary type III radio bursts  Edit Entry  Download Preprint  Delete Entry 

Key
Go to main E-Print pageGo to main E-Print page.
Previous AbstractPrevious Abstract.
Next AbstractNext Abstract.
Download PreprintDownload Preprint.
Submitter's HomepageSubmitters Homepage.
Edit EntryEdit Entry.
View All Abstracts By SubmitterView all abstracts by submitter.
Delete AbstractDelete abstract.

Latest Entries
Flare reconnection-driven magnetic field and Lorentz force variations at the Sun's surface
Why Does the Solar Corona Abnormally Rotate Faster Than the Photosphere?
Impacts On Proton Fluxes Observed During Different Interplanetary Conditions
Coronal Loop Seismology Using Standing Kink Oscillations With a Lookup Table
Data-Optimized Coronal Field Model: I. Proof of Concept
Coronal Bright Points
Difference of source regions between fast and slow coronal mass ejections
Invited Review: Signatures of Magnetic Flux Ropes in the Low Solar Atmosphere Observed in High Resolution
Do Kepler superflare stars really include slowly-rotating Sun-like stars ? - Results using APO 3.5m telescope spectroscopic observations and Gaia-DR2 data -
Magnetically Induced Current Piston for Generating Extreme-ultraviolet Fronts in the Solar Corona
Magnetic Field Dynamics and Varying Plasma Emission in Large-scale Coronal Loops
Nonlinear Evolution of Ion Kinetic Instabilities in the Solar Wind
What determines the X-ray intensity and duration of a solar flare?
Fast Magnetoacoustic Wave Trains with Time-dependent Drivers
Three-dimensional reconstruction of CME-driven shock-streamer interaction from radio observations: a different take on the diagnostics of coronal magnetic fields
The soft X-ray spectrometer polarimeter SolpeX
Variable emission mechanism of a Type IV radio burst
Inference of magnetic field strength and density from damped transverse coronal waves
Frequency-Distance Structure of Solar Radio Sources Observed by LOFAR
The birth of a coronal mass ejection

Related Pages
MSU Solar Physics.
Max Millennium Science Mail Archive.
Max Millennium Message of the Day Mail Archive.
Max Millennium Flare Catalog

Archive Maintainer
Alisdair Davey



© 2003 Solar Physics Group - Montana State University