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We study the temporal evolution of solar inertial modes over the solar cycle using observations from GONG and SDO/HMI. We focus on the high-latitude mode with azimuthal wavenumber $m=1$ and the equatorial Rossby modes with $3 \le m \le 16$.…

Solar and Stellar Astrophysics · Physics 2026-02-04 B Lekshmi , Zhi-Chao Liang , Laurent Gizon , Jordan Philidet , Kiran Jain

We observe the abrupt end of solar activity cycles at the Sun's equator by combining almost 140 years of observations from ground and space. These "terminator" events appear to be very closely related to the onset of magnetic activity…

Solar and Stellar Astrophysics · Physics 2019-07-17 Scott W. McIntosh , Robert J. Leamon , Ricky Egeland , Mausumi Dikpati , Yuhong Fan , Matthias Rempel

We derive analytical solutions and dispersion relations of global magnetic Poincar\'e (magneto-gravity) and magnetic Rossby waves in the approximation of shallow water magnetohydrodynamics. The solutions are obtained in a rotating spherical…

Astrophysics · Physics 2015-05-13 T. V. Zaqarashvili , R. Oliver , J. L. Ballester

Rossby waves drifting in the azimuthal direction are a common feature at the onset of thermal convective instability in a rapidly rotating spherical shell. They can also result from the destabilization of a Stewartson shear layer produced…

Geophysics · Physics 2015-05-13 R. Avalos-Zuniga , F. Plunian , K. H. R\" Adler

Over the course of their lifetimes, the rotation of solar-type stars goes through different phases. Once they reach the zero-age main sequence, their global rotation rate decreases during the main sequence until at least the solar age,…

Solar and Stellar Astrophysics · Physics 2022-03-14 Quentin Noraz , Allan-Sacha Brun , Antoine Strugarek , Gautier Depambour

(abridged) Context: Late-type stars such as the Sun rotate differentially due to the interaction of turbulent convection and rotation. Aims: The aim of the study is to investigate the effects of the thermal Prandtl number on the transition…

Solar and Stellar Astrophysics · Physics 2023-01-18 Petri J. Käpylä

The increasing richness of exoplanet observations has motivated a variety of three-dimensional atmospheric circulation models of these planets. Under strongly irradiated conditions, models of tidally locked, short-period planets (both hot…

Earth and Planetary Astrophysics · Physics 2015-05-27 Adam P. Showman , Lorenzo M. Polvani

Cloud cover at the planetary limb of water-rich Earth-like planets is likely to weaken chemical signatures in transmission spectra, impeding attempts to characterize these atmospheres. However, based on observations of Earth and solar…

Earth and Planetary Astrophysics · Physics 2023-07-14 Maureen Cohen , Massimo A. Bollasina , Denis E. Sergeev , Paul I. Palmer , Nathan J. Mayne

We studied the presence and spatiotemporal evolution of the quasi-biennial oscillations (QBOs) in the rotation rate residuals at target depths of 0.90$R_{\odot}$, 0.95$R_{\odot}$, and 0.99$R_{\odot}$ and at low (0 -- 30$^{\circ}$), mid (30…

Solar and Stellar Astrophysics · Physics 2021-10-20 Fadil Inceoglu , Rachel Howe , Paul T. M. Loto'aniu

Using the Hilbert-Huang transform technique, we investigate the midrange periodicities in solar radio flux at 2800 MHz (F10.7) and sunspot areas (SAs) from February 1, 1947 to September 30, 2016. The following prominent results are found:…

Solar and Stellar Astrophysics · Physics 2018-11-21 Ying Mei , Hui Deng , Feng Wang

Today's picture of the internal solar rotation rate profile results essentially from helioseismic analyses of frequency splittings of resonant acoustic waves. Here we present another, complementary estimation of the internal solar rotation…

Solar and Stellar Astrophysics · Physics 2020-02-17 Ariane Schad , Markus Roth

Helioseismology has provided very detailed inferences about rotation of the solar interior. Within the convection zone the rotation rate roughly shares the latitudinal variation seen in the surface differential rotation. The transition to…

Astrophysics · Physics 2009-11-11 J. Christensen-Dalsgaard

Using a nonlinear mean-field solar dynamo model, we study relationships between the amplitude of the `extended' mode of migrating zonal flows (`torsional oscillations') and magnetic cycles, and investigate whether properties the torsional…

Solar and Stellar Astrophysics · Physics 2020-09-02 V. V. Pipin , A. G. Kosovichev

It is widely reported that the power spectra of magnetic field and velocity fluctuations in the solar wind have power law scalings with inertial-range spectral indices of -5/3 and -3/2 respectively. Studies of solar wind turbulence have…

Solar and Stellar Astrophysics · Physics 2018-09-26 Trevor A. Bowen , Alfred Mallet , John W. Bonnell , Stuart D. Bale

(abridged) Context: Solar-like differential rotation is characterized by a rapidly rotating equator and slower poles. However, theoretical models and numerical simulations can result in a slower equator and faster poles when the rotation is…

Solar and Stellar Astrophysics · Physics 2014-10-17 P. J. Käpylä , M. J. Käpylä , A. Brandenburg

The solar cycle onset at mid-latitudes, the slow down of the sunspot drift toward the equator, the tail-like attachment and the overlap of successive cycles at the time of activity minimum are delicate issues in $\alpha\Omega$ dynamo wave…

Solar and Stellar Astrophysics · Physics 2016-09-07 R. Simoniello , S. C. Tripathy , K. Jain , F. Hill

Planetary-scale waves at the Venusian cloud-top cause periodic variations in both winds and ultraviolet (UV) brightness. While the wave candidates are the 4-day Kelvin wave and 5-day Rossby wave with zonal wavenumber 1, their temporal…

We analyze spectral properties of solar convection in the range of depths from 0 to 19~Mm using subsurface flow maps obtained by the time-distance heiioseismology analysis of solar-oscillation data from the Helioseismic and Magnetic Imager…

Solar and Stellar Astrophysics · Physics 2022-03-01 Alexander V. Getling , Alexander G. Kosovichev

The surface layers of the Sun are strongly stratified. In the presence of turbulence with a weak mean magnetic field, a large-scale instability resulting in the formation of non-uniform magnetic structures, can be excited over the scale of…

Solar and Stellar Astrophysics · Physics 2015-12-16 Illa R. Losada , A. Brandenburg , N. Kleeorin , Dhrubaditya Mitra , I. Rogachevskii

We study the solar-activity and solar-polarity dependence of galactic cosmic-ray intensity (CRI) on the solar and heliospheric parameters playing a significant role in solar modulation. We utilize the data for cosmic-ray intensity as…

Solar and Stellar Astrophysics · Physics 2014-04-07 O. P. M. Aslam , Badruddin