Results 51 to 60 of about 881 (218)

Photospheric high-frequency acoustic power excess in sunspot umbra: signature of magneto-acoustic modes [PDF]

, 2013
We present observational evidence for the presence of MHD (magnetohydrodynamic) waves in the solar photosphere deduced from SOHO/MDI (Solar and Heliospheric Observatory/Michelson Doppler Imager) Dopplergram velocity observations.
Shelyag, S., Thompson, Michael John, Zharkov, Sergei, Zharkov, S., M. J. Thompson, Fedun, V., S. Zharkov, Shelyag, Sergiy, Erdélyi, Robert, R. Erdélyi, Erdelyi, R., S. Shelyag, V. Fedun, Fedun, Viktor, Thompson, M.J.   +14 more
core   +1 more source

Is the Solar Chromosphere Heated by Acoustic Waves? [PDF]

The Astrophysical Journal, 2007
Space observations with TRACE have measured only 10% of the energy flux required to heat the nonmagnetic part of the solar chromosphere and have thereby called into question the theory of chromospheric heating by acoustic waves. To explain the deficit in the measured flux, heating by processes related to the magnetic field and the limited spatial ...
openaire   +1 more source

Newly Discovered Source of Turbulence and Heating in the Solar Chromosphere [PDF]

The Astrophysical Journal Letters, 2020
Abstract Above the Sun’s luminous photosphere lies the solar chromosphere, where the temperature increases from below 4000 K to over 1 million K. Though physicists do not understand the origin of these increases, they know it powers the solar wind with enormous consequences for the entire solar system.
Meers Oppenheim, Yakov Dimant, William Longley, Alex C. Fletcher   +3 more
openaire   +1 more source

Chromosphere of the quiet sun

Astronomy & Astrophysics
Context. The solar chromosphere is a dynamic and crucial interface between the solar interior and its interplanetary environment, regulating how energy is locally deposited into heat and transported into the upper atmospheric layers.
Noraz Q., Carlsson M., Aulanier G.
doaj   +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

SWIFF : space weather integrated forecasting framework [PDF]

, 2013
This research has received funding from the European Commission’s FP7 Program with the grant agreement SWIFF (Project No. 2633430, swiff.eu). The KU Leuven simulations were conducted on the computational resources provided by the PRACE Tier-0 Project No.
Viviane Pierrard, Bemporad, Alessandro, Parnell, Clare Elizabeth, O. Sebek, HENRI, PIERRE REMI ANTOINE, Mackay, Duncan H., Ondřej Šebek, Clare E. Parnell, Nordlund, Åke, Trávníček, Pavel M., Bemporad, A., Åke Nordlund, Mackay, Duncan Hendry, R. Keppens, A. Restante, Alessandro Bemporad, Pegoraro, Francesco, Parnell, C., V. Pierrard, Pierrard, Viviane, Markidis, Stefano,, D. Mackay, Keppens, R., Restante, A., Mackay, D., Faganello, Matteo, Stefano Markidis, Jacob Trier Frederiksen, Mackay, D.H., A. Bemporad, Faganello, M., Rony Keppens, Kris Borremans, Olshevsky, Vyacheslav, Pegoraro, F., Susino, R., M. Faganello V. Olshevsky, Parnell, Clare E., Borremans, K., K. Borremans, S. Poedts, Parnell, C.E., C. Parnell, Frederiksen, J., Lapenta, G., Califano, Francesco, S. Markidis, Francesco Califano, Restante, A.L., Borremans, Kris, Giovanni Lapenta, Pierrard, V., Keppens, Rony, Šebek, Ondřej, Trier Frederiksen, Jacob, Susino, Roberto, Lapenta, Giovanni, Henri, P., Califano, F., J. Frederiksen, Pavel M. Trávníček, Travnıcek, P., Pierre Henri, Restante, Anna Lisa, Markidis, S., Henri, Pierre, Stefaan Poedts, Vyacheslav Olshevsky, Markidis, Stefano, Duncan H. Mackay, Poedts, S., R. Susino, Frederiksen, Jacob Trier, Nordlund, A., G. Lapenta, Sebek, O., Anna Lisa Restante, Trávníček, P.M., Roberto Susino, Poedts, Stefaan, Olshevsky, V., A. Nordlund, Matteo Faganello, Francesco Pegoraro, Trávníček, Pavel M   +84 more
core   +1 more source

Chromospheric evaporation as the driver of helium enrichment in active region solar wind: A case study

Astronomy & Astrophysics
Context. The physical mechanisms of helium abundance (AHe) depletion in the corona and solar wind are closely linked to coronal heating, solar wind origin, and acceleration processes. The relationships between the AHe in the solar wind and the properties
Ma Chi, Fu Hui, Madjarska Maria S., Shi Xinzheng, Huang Zhenghua, Xia Lidong   +5 more
doaj   +1 more source

HEATING OF THE PARTIALLY IONIZED SOLAR CHROMOSPHERE BY WAVES IN MAGNETIC STRUCTURES [PDF]

The Astrophysical Journal Letters, 2016
ABSTRACT In this paper, we show a “proof of concept” of the heating mechanism of the solar chromosphere due to wave dissipation caused by the effects of partial ionization. Numerical modeling of non-linear wave propagation in a magnetic flux tube, embedded in the solar atmosphere, is performed by solving a system of single-fluid quasi ...
S. Shelyag, E. Khomenko, A. de Vicente, D. Przybylski   +3 more
openaire   +3 more sources

Solar Chromospheric Heating by Kinetic Alfvén Waves Based on the Three-fluid Model

The Astrophysical Journal
The heating mechanism of the solar chromosphere with a partially ionized plasma has been one of the challenging problems in solar physics. Kinetic Alfvén waves (KAWs) have been applied by many authors to study the heating of the corona and chromosphere ...
Jin-Run Ou, Ling Chen, De-Jin Wu, Chuan-Bing Wang   +3 more
doaj   +1 more source

Multifluid Simulation of Solar Chromospheric Turbulence and Heating Due to Thermal Farley–Buneman Instability

The Astrophysical Journal, 2023
Models fail to reproduce observations of the coldest parts of the Sun’s atmosphere, where interactions between multiple ionized and neutral species prevent an accurate MHD representation.
Samuel Evans, Meers Oppenheim, Juan Martínez-Sykora, Yakov Dimant, Richard Xiao   +4 more
doaj   +1 more source