Results 31 to 40 of about 1,264 (196)

Solar Mean Magnetic Field of the Chromosphere

, 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.
Nagaraju, K., Vishnu, M., Mathur, Harsh
core   +1 more source

The Sun and Solar-like Stars

, 2022
Lecture on the sun and solar-like stars. Chapter 0: Our perspective Chapter 1: The formation of the Sun Chapter 2: The first step: The luminosity of the Sun and what we learn from the spectrum Chapter 3. How does the sun produce its energy? Chapter
Guenther
core   +1 more source

Spectral Irradiance Observations and Projections for Solar Cycle 25

Earth and Space Science, Volume 13, Issue 4, April 2026.
Abstract The Ozone Monitoring Instrument (OMI) on the Aura satellite makes near‐daily measurements of solar spectral irradiance (SSI) at wavelengths between 265 and 500 nm for instrument calibration purposes. The low degradation and exceptional stability of OMI's calibration during its lifetime facilitates the creation of a new 18‐year OMI Version 7 ...
Matthew T. DeLand, Sergey V. Marchenko, Judith L. Lean, Odele Coddington   +3 more
wiley   +1 more source

Parker Solar Probe Observations of Proton Core‐Beam Distributions in Heliospheric Current Sheet Region: Quasilinear Instability Analysis Combined With Collisional Relaxation

Journal of Geophysical Research: Space Physics, Volume 131, Issue 4, April 2026.
Abstract Parker Solar Probe has been proven as instrumental for the observation of young solar wind. During the encounters E‐07 and E‐08, PSP recorded the core plus beaming protons crossing the heliospheric current Sheet region. When the observed PSP data is plotted in the temperature ratio versus parallel beta space, it is found that the occurrence ...
M. Rashid, P. H. Yoon, J. Huang, C. Salem, M. Sarfraz, S. Alnussirat, R. A. López, J. Seough, H. Xie, D. Larson, R. Livi   +10 more
wiley   +1 more source

Reconstruction of Two‐Dimensional Magnetohydrodynamic and Hall Magnetohydrodynamic Equilibria in Space Using Physics‐Informed Neural Networks

Journal of Geophysical Research: Machine Learning and Computation, Volume 3, Issue 2, April 2026.
Abstract We present a novel data analysis technique based on physics‐informed neural networks (PINNs) to reconstruct two‐dimensional (2D) magnetohydrodynamic (MHD) and Hall MHD equilibria in a space plasma from in situ spacecraft measurements. Our method incorporates the steady‐state MHD or Hall MHD equations—a set of partial differential equations ...
Hiroshi Hasegawa, Eunjin Choi, Kyoung‐Joo Hwang, Kyunghwan Dokgo   +3 more
wiley   +1 more source

Investigating Alfvénic wave propagation in coronal open-field regions

, 2015
The physical mechanisms behind accelerating solar and stellar winds are a long-standing astrophysical mystery, although recent breakthroughs have come from models invoking the turbulent dissipation of Alfvén waves.
Morton, Richard, Tomczyk, Steve, Pinto, Rui   +2 more
core   +1 more source

Reconstructing Historical Solar Indices for Predicting Past Space Weather Events

Space Weather, Volume 24, Issue 4, April 2026.
Abstract Modeling and forecasting the near‐Earth space environment, specifically the thermosphere, is particularly important because it affects the motion of low‐Earth orbit objects through atmospheric drag. Solar indices such as F10.7, S10.7, M10.7, and Y10.7 are commonly used as inputs to ionospheric and thermospheric density models.
Poshan Belbase, Denny M. Oliveira, Theodosios Chatzistergos, Gangkai Poh, Eftyhia Zesta   +4 more
wiley   +1 more source

Propagating and Stationary Bright Knots in the Quiet Sun

, 2022
The question of what heats the solar chromosphere and corona remains one of the most important puzzles in solar physics and astrophysics. Up to now, two mechanisms are considered to work in heating the chromosphere and corona: magnetic reconnection and ...
Jun Zhang, Tao Ding, Yue Fang, Yongyuan Xiang, Feng Chen, Ting Li, Xiaoli Yan, Zhiping Song, Yijun Hou, Zhong Liu   +9 more
core   +1 more source

Chromospheric activity of nearby Sun-like stars [PDF]

Astronomy & Astrophysics, 2020
Context.The chromospheric emission in the cores of the Ca IIH & K lines of late-type dwarfs is a well known indicator of magnetic activity that decreases with increasing stellar age.Aims.I use this indicator to investigate the formation history of nearby G- and early K-type stars with origins at galactocentric distances similar to that of the ...
openaire   +1 more source

Searching for Rotational X‐Ray Modulation on TIC 277539431

Astronomische Nachrichten, Volume 347, Issue 3, March 2026.
ABSTRACT TIC 277539431, a fast rotating M7 dwarf, was detected to host the highest latitude flare to date at 81°$$ {81}^{{}^{\circ}} $$. Magnetic activity like stellar flares occurring at high latitude indicate occurrence of coronal loops at these latitudes on fully‐convective M dwarfs. In contrast, sunspots usually occur below 30°$$ {30}^{{}^{\circ}} $
Desmond Dsouza, Katja Poppenhäger, Ekaterina Ilin   +2 more
wiley   +1 more source