Search Publications
Formation of Torus-Unstable Flux Ropes and Electric Currents in Erupting Sigmoids
Aulanier, G.; Démoulin, P.; Török, T. +1 more
We analyze the physical mechanisms that form a three-dimensional coronal flux rope and later cause its eruption. This is achieved by a zero-β magnetohydrodynamic (MHD) simulation of an initially potential, asymmetric bipolar field, which evolves by means of simultaneous slow magnetic field diffusion and sub-Alfvénic, line-tied shearing motions in …
Dichotomy of Solar Coronal Jets: Standard Jets and Blowout Jets
Cirtain, Jonathan W.; Moore, Ronald L.; Sterling, Alphonse C. +1 more
By examining many X-ray jets in Hinode/X-Ray Telescope coronal X-ray movies of the polar coronal holes, we found that there is a dichotomy of polar X-ray jets. About two thirds fit the standard reconnection picture for coronal jets, and about one third are another type. We present observations indicating that the non-standard jets are counterparts…
Quiescent Prominence Dynamics Observed with the Hinode Solar Optical Telescope. I. Turbulent Upflow Plumes
Magara, Tetsuya; Shimizu, Toshifumi; Okamoto, Takenori J. +10 more
Hinode/Solar Optical Telescope (SOT) observations reveal two new dynamic modes in quiescent solar prominences: large-scale (20-50 Mm) "arches" or "bubbles" that "inflate" from below into prominences, and smaller-scale (2-6 Mm) dark turbulent upflows. These novel dynamics are related in that they are always dark in visible-light spectral bands, the…
Reconnection Outflows and Current Sheet Observed with Hinode/XRT in the 2008 April 9 "Cartwheel CME" Flare
Reeves, Katharine K.; Longcope, Dana W.; Savage, Sabrina L. +2 more
Supra-arcade downflows (SADs) have been observed with Yohkoh/SXT (soft X-rays (SXR)), TRACE (extreme ultraviolet (EUV)), SOHO/LASCO (white light), SOHO/SUMER (EUV spectra), and Hinode/XRT (SXR). Characteristics such as low emissivity and trajectories, which slow as they reach the top of the arcade, are consistent with post-reconnection magnetic fl…
Quasi-periodic Propagating Signals in the Solar Corona: The Signature of Magnetoacoustic Waves or High-velocity Upflows?
De Pontieu, Bart; McIntosh, Scott W.
Since the discovery of quasi-periodic propagating oscillations with periods of order 3-10 minutes in coronal loops with TRACE and SOHO/EIT (and later with STEREO/EUVI and Hinode/EIS), they have been almost universally interpreted as evidence for propagating slow-mode magnetoacoustic waves in the low plasma β coronal environment. Here we show that …
Nonlinear Propagation of Alfvén Waves Driven by Observed Photospheric Motions: Application to the Coronal Heating and Spicule Formation
Matsumoto, Takuma; Shibata, Kazunari
We have performed MHD simulations of Alfvén wave propagation along an open flux tube in the solar atmosphere. In our numerical model, Alfvén waves are generated by the photospheric granular motion. As the wave generator, we used a derived temporal spectrum of the photospheric granular motion from G-band movies of Hinode/Solar Optical Telescope. It…
Coronal Rain as a Marker for Coronal Heating Mechanisms
Shibata, K.; Vissers, G.; Antolin, P.
Reported observations in Hα, Ca II H, and K or other chromospheric lines of coronal rain trace back to the days of the Skylab mission. Corresponding to cool and dense plasma, coronal rain is often observed falling down along coronal loops in active regions. A physical explanation for this spectacular phenomenon has been put forward thanks to numer…
Observation of Kink Instability During Small B5.0 Solar Flare on 2007 June 4
Srivastava, A. K.; Khodachenko, M. L.; Kumar, Pankaj +1 more
Using multi-wavelength observations of SOHO/MDI, SOT-Hinode/blue-continuum (4504 Å), G band (4305 Å), Ca II H (3968 Å), and TRACE 171 Å, we present the observational signature of a highly twisted magnetic loop in AR 10960 during the period 04:43 UT-04:52 UT on 2007 June 4. SOT-Hinode/blue-continuum (4504 Å) observations show that penumbral filamen…
Multiwavelength Observations of Small-scale Reconnection Events Triggered by Magnetic Flux Emergence in the Solar Atmosphere
Aulanier, G.; Guglielmino, S. L.; Bellot Rubio, L. R. +3 more
The interaction between emerging magnetic flux and the pre-existing ambient field has become a "hot" topic for both numerical simulations and high-resolution observations of the solar atmosphere. The appearance of brightenings and surges during episodes of flux emergence is believed to be a signature of magnetic reconnection processes. We present …
Three-dimensional Morphology of a Coronal Prominence Cavity
Seaton, D. B.; Schmieder, B.; de Toma, G. +16 more
We present a three-dimensional density model of coronal prominence cavities, and a morphological fit that has been tightly constrained by a uniquely well-observed cavity. Observations were obtained as part of an International Heliophysical Year campaign by instruments from a variety of space- and ground-based observatories, spanning wavelengths fr…