English
Related papers

Related papers: Time-Distance Modelling In A Simulated Sunspot Atm…

200 papers

We present a three-dimensional numerical model for the generation and evolution of the magnetic field in the solar convection zone, in which sunspots are produced and contribute to the cyclic reversal of the large-scale magnetic field. We…

Solar and Stellar Astrophysics · Physics 2018-01-30 Rohit Kumar , Laurène Jouve , Rui F. Pinto , Alexis P. Rouillard

We report on a systematic center-to-limb variation in measured helioseismic travel times, which must be taken into account for an accurate determination of solar interior meridional flows. The systematic variation, found in time-distance…

Solar and Stellar Astrophysics · Physics 2015-06-04 Junwei Zhao , Kaori Nagashima , R. S. Bogart , A. G. Kosovichev , T. L. Duvall

To model the interaction between the solar wind and the interstellar wind, magnetic fields must be included. Recently Opher et al. 2003 found that, by including the solar magnetic field in a 3D high resolution simulation using the…

The purpose of this white paper is to put together a coherent vision for the role of helioseismic monitoring of magnetic activity in the Sun's far hemisphere that will contribute to improving space weather forecasting as well as fundamental…

Magnetic quenching of turbulent thermal diffusivity leads to instability of the large-scale field with the production of spatially isolated regions of enhanced field. This conclusion follows from a linear stability analysis in the framework…

Solar and Stellar Astrophysics · Physics 2019-05-01 Leonid L. Kitchatinov

We present the results of numerical simulations of shock wave-driven jets in the solar atmosphere. The dependence of observable quantities like maximum velocity and deceleration on parameters such as the period and amplitude of initial…

Astrophysics · Physics 2011-02-11 L. Heggland , B. De Pontieu , V. H. Hansteen

Sunspots are regions of decreased brightness on the visible surface of the Sun (photosphere) that are associated with strong magnetic fields. They have been found to be locations associated with solar flares, which occur when energy stored…

Solar and Stellar Astrophysics · Physics 2013-01-24 Sophie A. Murray

Quiet-Sun regions cover most of the Sun's surface; its magnetic fields contribute significantly to the solar chromospheric and coronal heating. However, characterizing the magnetic fields of the quiet Sun is challenging due to their weak…

Solar and Stellar Astrophysics · Physics 2024-12-02 Jiayi Liu , Xudong Sun , Peter W. Schuck , Sarah A. Jaeggli

A theoretical sunspot model is provided including magnetic suppression of the diffusivities and also a strong stratification of density and temperature. Heat diffusion alone with given magnetic field and zero mean flow only produces (after…

Astrophysics · Physics 2007-05-23 L. L. Kitchatinov , G. Ruediger

Helioseismic and magnetohydrodynamic waves are abundant in and above sunspots. Through cross-correlating oscillation signals in the photosphere observed by the SDO/HMI, we reconstruct how waves propagate away from virtual wave sources…

Solar and Stellar Astrophysics · Physics 2015-08-19 Junwei Zhao , Ruizhu Chen , Thomas Hartlep , Alexander G. Kosovichev

We processed magnetograms that were obtained with the Michaelson Doppler Imager onboard the Solar and Heliospheric Observatory (SOHO/MDI). The results confirm the basic properties of long-period oscillations of sunspots that have previously…

Solar and Stellar Astrophysics · Physics 2014-12-15 V. I. Efremov , L. D. Parfinenko , A. A. Solovev , E. A. Kirichek

Full-disk observations from missions such as the SDO and SOHO have enabled comprehensive studies of solar oscillations and dynamics. Interpreting helioseismic and photospheric data is complicated by systematic center-to-limb variations. To…

Solar and Stellar Astrophysics · Physics 2026-04-06 Irina N. Kitiashvili

Context: Helioseismology aims to infer the properties of the solar interior by analyzing observations of acoustic oscillations. The interpretation of the helioseismic data is however complicated by the non-trivial relationship between…

Solar and Stellar Astrophysics · Physics 2025-10-29 D. Fournier , N. M. Kostogryz , L. Gizon , J. Schou , V. Witzke , A. I. Shapiro , I. Milic

In addition to sunspots, which represent the most easily visualized manifestation of solar magnetism, cutting-edge observations of the solar atmosphere have uncovered a plethora of magnetic flux tubes, down to the resolving power of modern…

Solar and Stellar Astrophysics · Physics 2025-02-27 M. Stangalini , G. Verth , V. Fedun , D. Perrone , M. Berretti , P. Bushby , S. Jafarzadeh , D. B. Jess , F. Giannattasio , P. H. Keys , R. Bruno , F. Berrilli

Although the magnetic fields in the quiet Sun account for the majority of the magnetic energy in the solar photosphere, inferring their exact spatial distribution, origin, and evolution poses an important challenge because the signals lie…

Solar and Stellar Astrophysics · Physics 2024-10-03 Elias Ebert , Ivan Milic , Juan Manuel Borrero

We perform radiative magnetohydrodynamic calculations for the solar quiet region to investigate the dependence of statistical flow on magnetic properties and the three-dimensional (3D) structure of magnetic patches in the presence of…

Solar and Stellar Astrophysics · Physics 2021-03-17 K. Takahata , H. Hotta , Y. Iida , T. Oba

We analyse the temporal evolution of the inclination component of the magnetic field vector for the penumbral area of 25 isolated sunspots. Compared to previous works, the use of data from the HMI instrument aboard the SDO observatory…

Solar and Stellar Astrophysics · Physics 2020-03-11 A. B. Griñón-Marín , A. Pastor Yabar , H. Socas-Navarro , R. Centeno

Data obtained over the last three solar cycles have been analysed to reveal the relationships between the intensity of the photospheric field measured along the line of sight by the WSO group at heliolatitudes from -75 to 75 degrees and the…

Geophysics · Physics 2018-02-14 E. A. Gavryuseva

Accurate modeling of the Sun's coronal magnetic field and solar wind structures require inputs of the solar global magnetic field, including both the near and far sides, but the Sun's far-side magnetic field cannot be directly observed.…

Solar and Stellar Astrophysics · Physics 2023-01-04 Ruizhu Chen , Junwei Zhao , Shea Hess Webber , Yang Liu , J. Todd Hoeksema , Marc L. Derosa

Many previous studies have shown that magnetic fields as well as sunspot structures present rapid and irreversible changes associated with solar flares. In this paper we first use five X-class flares observed by SDO/HMI to show that not…

Solar and Stellar Astrophysics · Physics 2016-08-17 Yongliang Song , Mei Zhang