XPOW: X-Ray Sun Two-Month Mashup
SOT POD: 2013 Oct 23 Flare
XPOW: Full-Sun Images in Three Temperature Ranges
XPOW: X1.1 Flare with CME on November 10th, 2013
XPOW: Heart-shaped productive Active Region 11875
New XRT Observation Resources!: The XRT Team has released two new resources for browsing XRT data. First, we have a revamped synoptic gallery. All of XRT's twice-daily full sun images are on display, and starting in June of 2013, each image is a composite of 3 exposures (long-medium-short) instead of 2. This provides a more lovely showing of the broad dynamic range the sun is currently displaying in its maximum activity phase. Next, we've got the XRT Flare Catalog. The catalog includes basic information for all the flares that have occurred during the Hinode mission, along with summaries and preview movies of XRT's observations for each event. Links to both resources can be found under the "Data" tab in the sidebar and under "Observations" on the Mission Ops page. XRT Synoptic Gallery XRT Flare Catalog
XPOW: Solar Eclipse of November 3rd, 2013
XRT Calibration Update: The calibration of the instrument response functions has been updated, and the XRT response software in SolarSoft has also been updated accordingly (e.g. make_xrt_wave_resp.pro, xrt_teem.pro, xrt_eff_area.pro, etc.). The change adjusts some of the filter thicknesses to reflect the analysis of Narukage et al. 2013. As a result, the estimated effective areas of those filters (med-Be, med-Al, thick-Be, & thick-Al) have changed. Click here for a plot of the updated temperature response functions (dotted lines indicated the previous calibration). The new calibration files have been made available in SolarSoft. Please ensure that your SSW IDL libraries are up to date. See program headers and/or the XRT Analysis Guide for documention, and please direct questions and bug reports to xrt_manager [at] head [dot] cfa [dot] harvard [dot] edu.
XPOW: More Flares from AR 11882!
XPOW: M-Flares with CMEs on October 26th & 27th
SOT POD: Sunspots in Active Region 11850
XPOW: Sigmoid Eruptions on August 7th, 2013
XPOW: B Flare on September 23rd
EIS Nugget: Clear Evidence for Hot Fast Flow above a Solar Flare Arcade...
XRT Thesis Updates: Congratulations from the XRT Team to Lucas Tarr and Will Hanneman for recently completing their respective theses. The newly minted Dr. Tarr successfully defended his PhD dissertation on "Energetic Consequences of Flux Emergence", and Mr. Hanneman completed a master's thesis on the "Thermal Structure of Current Sheets and Supra-Arcade Downflows".
XRT in the News: Slate Article (Bad Astronomy) -- Taking an X-Ray of an Eclipse
XPOW: Slow CME with Supra-Arcade Downflows
SOT POD: Sunspots in Active Region 11836
XPOW: M Flares and Sigmoid Sea Creatures
SOT POD: Sunspot in Active Region 11818
XPOW: Tiny Active Region Bright Point
XPOW: Flaring Loops in Active Region 11755
Congratulations to the IRIS team on a successful launch!
EIS Nugget: The Cold Shoulder: Emission Measure Distributions of Active Region Cores...
XPOW: Sigmoid Dynamics from April 20-22, 2013
XPOW: M5.0 Flare of 22nd, 2013
New XRT Publication:
The paper "Indeterminacy and instability in Petschek reconnection" by Forbes, Priest, Seaton, and Litvinenko has been accepted for
publication in Physics of Plasmas.
In this paper, two puzzling aspects of Petschek's model for fast reconnection are explained. One is its failure to occur in plasma simulations with uniform resistivity. The other is its inability to provide anything more than an upper limit for the reconnection rate. The authors found that previously published analytical solutions based on Petschek's model are structurally unstable if the electrical resistivity is uniform. The structural instability is associated with the presence of an essential singularity at the X-line that is unphysical. By requiring that such a singularity not exist, the authors obtain a formula that predicts a specific rate of reconnection. For uniform resistivity, reconnection can only occur at the slow, Sweet-Parker rate. For nonuniform resistivity, reconnection can occur at a much faster rate provided that the resistivity profile is not too flat near the X-line. If this condition is satisfied, then the scale length of the nonuniformity determines the reconnection rate.
SOT POD: 2013 May 14 Post Flare Activity
XPOW: Three X-Flares in 24 Hours!
EIS Nugget: Using EIS to measure the coronal magnetic field...
XRT News: Big Pic: Watch The Moon Swallow The Sun In X-Ray -- Popsci article
XPOW: Solar Eclipse of May 10th, 2013
XPOW: Sigmoid Eruption on March 15th, 2013
XPOW: Limb CME on Feb 15th, 2013
SOT POD: 2013 Mar 17 Coronal Jets
SOT POD: Bubbling Action
XPOW: Coronal Cavity with Bright Core
XPOW: Plasma Flows Along Coronal Loops
EIS Nugget: What can we deduce from the 3D geometry of AR upflows?...
XRT News: Wired Science Space Photo of the Day!
XRT News: Happy Valentine's Day! Love, Your Sun -- Popsci article
XRT News: Happy Cosmic Valentine's Day! -- XRT featured as part of a Slate compilation
XPOW: Happy Valentine's Day!
New XRT Publication:
The paper "Turbulent Dynamics in Solar Flare Sheet Structures Measured with Local Correlation Tracking" by David E. McKenzie has been accepted for publication in The Astrophysical Journal.
In this paper, motions in flare plasmas are monitored with Local Correlation Tracking (first time LCT has been used in the corona, maybe?). The velocity field of the plasma is determined, and
from that a vorticity can be inferred. The paper demonstrates that recent developments in high-resolution, high-cadence imaging of the corona make it possible to study turbulence in the flare
plasma. Turbulence has long been the domain of spectroscopy, where turbulence is inferred from nonthermal broadening of emission lines. Such 1-dimensional studies (i.e., velocities along the
line of sight) have been all that was available. The imagery from XRT and AIA bring two additional spatial dimensions into play, and combination of the imagery with spectroscopy offers to
complete the set. The reason it matters is this--- turbulence creates small length scales, and small length scales enable reconnection. In the words of the Heliophysics Roadmap, it's all about
"the microphysics of magnetic reconnection by determining the kinetic processes responsible".
Although some dynamic activity was seen in other parts of the eruptive structure, the most notable feature was apparent rotation in the southernmost part of the extended coronal structure,
immediately above the limb. The LCT allows the velocity field to be mapped, and then one can explore the plasma motion via either Eulerian or Lagrangian techniques. As an example, the
vorticity has been calculated in this rotating feature (context and vortex map).
SOT POD: Fluid Motion
EIS Nugget: EIS Observations of Solar Mass Eruptions...
XPOW: Fifteen Active Regions in One Image