Search Publications
Implications of High-density, High-temperature Ridges Observed in Some Two-ribbon Flares
Qiu, Jiong; Longcope, Dana
Several two-ribbon solar flares observed on the disk, notably including the Bastille flare of 2000 July 14, show an extended ridge of plasma running along the loop tops of the post-reconnection arcade. In that and two more recent examples, the ridge is visible in emission by Fe XXIV at roughly 17 MK, with a high, steadily increasing emission measu…
Deep-learning Reconstruction of Sunspot Vector Magnetic Fields for Forecasting Solar Storms
Dhuri, Dattaraj B.; Bhattacharjee, Shamik; Hanasoge, Shravan M. +1 more
Solar magnetic activity produces extreme solar flares and coronal mass ejections, which pose grave threats to electronic infrastructure and can significantly disrupt economic activity. It is therefore important to appreciate the triggers of explosive solar activity and develop reliable space weather forecasting. Photospheric vector magnetic field …
Toward Understanding the B[e] Phenomenon. VIII. Nature and Variability of IRAS 07080+0605
Miroshnichenko, A. S.; Manset, N.; Zharikov, S. V. +13 more
We report the results of spectroscopic and photometric observations of the emission-line object IRAS 07080+0605 carried out in 2004-2021. We found that the object is significantly underluminous for its spectroscopic properties (T eff = 8500 ± 500 K, $\mathrm{log}$ g = 2.0 ± 0.5), if a strong visual attenuation by a factor of ~43 found t…
Remote Sensing of Coronal Forces during a Solar Prominence Eruption
Thompson, B. J.; DeVore, C. R.; Uritsky, V. M.
We present a new methodology-the Keplerian Optical Dynamics Analysis (KODA)-for quantifying the dynamics of erupting magnetic structures in the solar corona. The technique involves adaptive spatiotemporal tracking of propagating intensity gradients and their characterization in terms of time-evolving Keplerian areas swept out by the position vecto…
Comparing the Performance of a Solar Wind Model from the Sun to 1 au Using Real and Synthetic Magnetograms
Yeates, Anthony R.; Cohen, Ofer; Munoz-Jaramillo, Andres +1 more
The input of the solar wind models plays a significant role in accurate solar wind predictions at 1 au. This work introduces a synthetic magnetogram produced from a dynamo model as an input for magnetohydrodynamics simulations. We perform a quantitative study that compares the space weather modeling framework (SWMF) results for the observed and sy…
The Young Embedded Disk L1527 IRS: Constraints on the Water Snowline and Cosmic-Ray Ionization Rate from HCO+ Observations
Bergin, Edwin A.; Harsono, Daniel; Tobin, John J. +3 more
The water snowline in circumstellar disks is a crucial component in planet formation, but direct observational constraints on its location remain sparse owing to the difficulty of observing water in both young embedded and mature protoplanetary disks. Chemical imaging provides an alternative route to locate the snowline, and HCO+ isotop…
Evidence of the Alfvén Transition Layer and Particle Precipitation in the Cusp Region: 3D Global PIC Simulation of the Solar Wind-Earth Magnetosphere Interaction
Lembège, B.; Cai, D. S.; Ekawati, Sri
A transition layer, named the Alfvénic transition layer (or ATL), has been clearly evidenced near the outer boundary of the cusp by experimental observations from the Cluster mission. This layer characterized by a local value of Log M A ~ 1, where M A is the Alfvén Mach number, allows the bulk flow to transit from super-Alfvé…
Solar Wind Electron Pressure Gradients, Suprathermal Spectral Hardness, and Strahl Localization Organized by Single-point Measurements of 0.1 nV m-1 Ambipolar E ∥
Scudder, Jack D.
A new, fast technique to measure the solar wind's ambipolar E ∥ routinely with 10% precision and accuracy is demonstrated using 4 yr of 1 au electron data from the Wind 3DP experiment. The 3DP electron instrument duty cycle determines E ∥ ≃ 0.1 nV m-1 from a single spectrum over much shorter time intervals than tho…
X-Ray Observation of the Roche-lobe-filling White Dwarf plus Hot Subdwarf System ZTF J213056.71+442046.5
Tiengo, A.; Mereghetti, S.; Esposito, P. +9 more
ZTF J213056.71+442046.5 is the prototype of a small class of recently discovered compact binaries composed of a white dwarf and a hot subdwarf that fills its Roche lobe. Its orbital period of only 39 minutes is the shortest known for the objects in this class. Evidence for a high orbital inclination (i = 86°) and for the presence of an accretion d…
Fine Structures of the Inner Solar Corona and the Associated Magnetic Topology
Stenborg, Guillermo; Ko, Yuan-Kuen; Lionello, Roberto +3 more
We present the fine structure of the inner solar corona between 1.65 and 3.0 solar radii as revealed by the STEREO-A COR1 white-light coronagraph from 2008 June 20 to July 31. The COR1 imaging data were wavelet processed to enhance the intensity contrast of coronal features. The constructed limb synoptic maps at a range of altitudes show the evolu…