Results 41 to 50 of about 682 (184)

Observing the Solar Chromosphere

, 2007
This review is split into two parts: one on chromospheric line formation in answer to the frequent question "where is my line formed", and one presenting state-of-the-art imagery of the chromosphere. In the first part I specifically treat the formation of the Na D lines, Ca II H & K, and Halpha.
openaire   +4 more sources

Comparison of Solar Imaging Feature Extraction Methods in the Context of Space Weather Prediction With Deep Learning‐Based Models

Journal of Geophysical Research: Machine Learning and Computation, Volume 2, Issue 3, September 2025.
Abstract Recently, many machine learning‐based models have been developed to predict geomagnetic activity several days in advance directly from space‐borne solar imaging. To better understand and improve these models, we compare dimensionality reduction techniques to extract abstract features from solar images for space weather‐related downstream tasks.
Maria Tahtouh, Guillerme Bernoux, Antoine Brunet, Denis Standarovski, Gautier Nguyen, Angélica Sicard   +5 more
wiley   +1 more source

Calcium Bright Knots and the Formation of Chromospheric Anemone Jets on the Sun

The Astrophysical Journal Letters
Space-based observations show that the solar atmosphere from the solar chromosphere to the solar corona is filled with small-scale jets and is linked with small-scale explosions.
Kunwar Alkendra Pratap Singh, Keisuke Nishida, Kazunari Shibata   +2 more
doaj   +1 more source

Solar mean magnetic field of the chromosphere

Journal of Astrophysics and Astronomy, 2023
The Solar Mean Magnetic Field (SMMF) is the mean value of the line of sight (LOS) component of the solar vector magnetic field averaged over the visible hemisphere of the Sun. So far, the studies on SMMF have mostly been confined to the magnetic field measurements at the photosphere. In this study, we calculate and analyse the SMMF using magnetic field
M. Vishnu, K. Nagaraju, Harsh Mathur
openaire   +2 more sources

Deriving the Coronal Separatrix‐Web With the WSA Model

Journal of Geophysical Research: Space Physics, Volume 130, Issue 8, August 2025.
Abstract We demonstrate a new capability of the Wang‐Sheeley‐Arge (WSA) model to routinely derive the coronal separatrix web (S‐web) as a standard data product. We describe our methodology for deriving the squashing factor (Q $Q$) and we use Carrington rotation (CR) 2109 to illustrate the validation of our output with that derived from the POT3D model.
Samantha Wallace, Aleida K. Higginson, David G. Simpson, Nicholeen M. Viall, Peter Wyper, C. Nick Arge   +5 more
wiley   +1 more source

Solar Wind Heavy Ions and Alpha Particles Within Earth's Magnetosphere and Their Variability With Upstream Conditions

Journal of Geophysical Research: Space Physics, Volume 130, Issue 8, August 2025.
Abstract Working toward the goal of understanding solar wind (SW) entry to the Earth's magnetosphere, this study examines solar‐origin ion composition in the magnetotail. During its trajectory, Wind spent a significant amount of time in the Earth's magnetotail, where its SupraThermal Ion Composition Spectrometer (STICS) measured the mass and mass per ...
S. Colón‐Rodríguez, M. W. Liemohn, J. M. Raines, S. T. Lepri   +3 more
wiley   +1 more source

Measurement of Turbulence Injection Scale Down to the Chromosphere

The Astrophysical Journal Letters
The solar atmosphere displays a sharp temperature gradient, starting from spicules in the chromosphere at 2 × 10 ^4 K, outward into the corona exceeding ${10}^{6}$ K.
Zachary Bailey, Riddhi Bandyopadhyay, Shadia Habbal, Miloslav Druckmüller   +3 more
doaj   +1 more source

Alfvén wave dissipation in the solar chromosphere [PDF]

Nature Physics, 2018
Magneto-hydrodynamic (MHD) Alfv n waves have been a focus of laboratory plasma physics and astrophysics for over half a century. Their unique nature makes them ideal energy transporters, and while the solar atmosphere provides preferential conditions for their existence, direct detection has proved difficult as a result of their evolving and dynamic ...
Samuel D. T. Grant, David B. Jess, Teimuraz V. Zaqarashvili, Christian Beck, Hector Socas-Navarro, Markus J. Aschwanden, Peter H. Keys, Damian J. Christian, Scott J. Houston, Rebecca L. Hewitt   +9 more
openaire   +4 more sources

RADIATING CURRENT SHEETS IN THE SOLAR CHROMOSPHERE [PDF]

The Astrophysical Journal, 2012
An MHD model of a Hydrogen plasma with flow, an energy equation, NLTE ionization and radiative cooling, and an Ohm's law with anisotropic electrical conduction and thermoelectric effects is used to self-consistently generate atmospheric layers over a $50$ km height range.
Goodman, Michael L., Judge, Philip G.
openaire   +2 more sources

Slow Solar Wind: Origin in an Independent Small‐Scale Solar Dynamo

Geophysical Research Letters, Volume 52, Issue 13, 16 July 2025.
Abstract Separation of the solar wind (SW) into three flow types (coronal mass ejections (CMEs), high speed streams (HSSs), and slow solar wind (SSW)) reveals an inverse relationship between the percentage of time Earth spends in SSW during a year and its annually averaged magnetic field strength (B).
E. W. Cliver, I. G. Richardson, S. F. Martin   +2 more
wiley   +1 more source