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Related papers: The Solar Wind Angular Momentum Flux as Observed b…

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The strength and morphology of the Sun's magnetic field evolves significantly during the solar cycle, with the overall polarity of the Sun's magnetic field reversing during the maximum of solar activity. Long-term changes are also observed…

Solar and Stellar Astrophysics · Physics 2023-11-01 Adam J. Finley , Allan Sacha Brun

The subject of switchbacks, defined either as large angular deflections or polarity reversals of the magnetic field, has generated substantial interest in the space physics community since the launch of Parker Solar Probe (PSP) in 2018.…

The proton temperature anisotropy in the solar wind exhibits apparent bounds which are compatible with the theoretical constraints imposed by temperature-anisotropy driven kinetic instabilities. Recent statistical analyses based on…

Space Physics · Physics 2014-09-12 Petr Hellinger , Pavel M. Travnicek

Studies of solar wind turbulence traditionally employ high-resolution magnetic field data, but high-resolution measurements of ion and electron moments have been possible only recently. We report the first turbulence studies of ion and…

On the main sequence, low-mass and solar-like stars are observed to spin-down over time, and magnetized stellar winds are thought to be predominantly responsible for this significant angular momentum loss. Previous studies have demonstrated…

Solar and Stellar Astrophysics · Physics 2022-02-02 Lewis G. Ireland , Sean P. Matt , Charlie R. Davey , Owain L. Harris , Tobias W. Slade-Harajda , Adam J. Finley , Claudio Zanni

Because of its distinctive compositional properties and variability, low-speed ($\lesssim 450$ km s$^{-1}$) solar wind is widely believed to originate from coronal streamers, unlike high-speed wind, which comes from coronal holes. An…

Solar and Stellar Astrophysics · Physics 2021-04-16 Y. -M. Wang , Y. -K. Ko

We measure the axisymmetric transport of magnetic flux on the Sun by cross-correlating narrow strips of data from line-of-sight magnetograms obtained at a 96-minute cadence by the MDI instrument on the ESA/NASA SOHO spacecraft and then…

Solar and Stellar Astrophysics · Physics 2011-03-30 David H. Hathaway , Lisa Rightmire

Solar coronal holes are sources of high-speed solar wind streams, which cause persistent geomagnetic activity especially at high latitudes. Here we estimate seasonal solar wind speeds at 1 AU for the last 100 years using high-latitude…

Space Physics · Physics 2017-02-22 Kalevi Mursula , Lauri Holappa , Renata Lukianova

The heating and acceleration of the solar wind remains one of the fundamental unsolved problems in heliophysics. It is usually observed that the proton temperature $T_i$ is highly correlated with the solar wind speed $V_{SW}$, while the…

The slow solar wind exhibits strong variability on timescales from minutes to days, likely related to magnetic reconnection processes in the extended solar corona. Higginson2017b presented a numerical magnetohydrodynamic simulation which…

Solar and Stellar Astrophysics · Physics 2018-05-23 Aleida K. Higginson , Benjamin J. Lynch

We present new models for the rotational evolution of solar-like stars between 1 Myr and 10 Gyr with the aim to reproduce the distributions of rotational periods observed for star forming regions and young open clusters within this age…

Solar and Stellar Astrophysics · Physics 2015-06-16 Florian Gallet , Jérôme Bouvier

For the past 30+ years, the magnetic expansion factor ($f_s$) has been used in empirical relationships to predict solar wind speed ($v_{obs}$) at 1 AU, based on an inverse relationship between these two quantities. Coronal unipolar…

Solar and Stellar Astrophysics · Physics 2020-08-03 Samantha Wallace , Charles N. Arge , Nicholeen M. Viall , Ylva Pihlstrom

Rotation periods are now available for ~500 pre-main sequence and recently arrived main sequence stars of solar-like mass (0.4-1.2 M_sun) in five nearby young clusters: the Orion Nebula Cluster, NGC 2264, alpha Per, IC 2602 and the…

Astrophysics · Physics 2009-11-13 W. Herbst , R. Mundt

An empirical model for forecasting solar wind speed related geomagnetic events is presented here. The model is based on the estimated location and size of solar coronal holes. This method differs from models that are based on photospheric…

Astrophysics · Physics 2008-11-26 S. Robbins , C. J. Henney , J. W. Harvey

The effects of the stellar rotation and the consequent azimuthal stellar wind flow in Parker's [9] hydrodynamic stellar wind model are discussed. Of special interest is the emergence of a whole new hydrodynamic physics via a new critical…

Plasma Physics · Physics 2018-09-17 B. K. Shivamoggi

Using data from orbits one to eleven of the Parker Solar Probe (PSP) mission, the magnetic field spectral index was measured across a range of heliocentric distances. The previously observed transition between a value of $-5/3$ far from the…

Solar and Stellar Astrophysics · Physics 2023-07-11 J. R. McIntyre , C. H. K. Chen , A. Larosa

An accurate solar wind speed model is important for space weather predictions, catastrophic event warnings, and other issues concerning solar wind - magnetosphere interaction. In this work, we construct a model based on convolutional neural…

Solar and Stellar Astrophysics · Physics 2023-04-05 Rong Lin , Zhekai Luo , Jiansen He , Lun Xie , Chuanpeng Hou , Shuwei Chen

Solar Orbiter will observe the Sun and the inner heliosphere to study the connections between solar activity, coronal structure, and the origin of the solar wind. The plasma instruments on board Solar Orbiter will determine the…

Space Physics · Physics 2020-01-08 Georgios Nicolaou , Daniel Verscharen , Robert T. Wicks , Christopher J. Owen

We present self-consistent numerical simulations of the sun's convection zone and radiative interior using a two-dimensional model of its equatorial plane. The background reference state is a one-dimensional solar structure model. Turbulent…

Astrophysics · Physics 2008-11-26 Tamara M. Rogers , Gary A. Glatzmaier

Parker Solar Probe (PSP) is providing an unprecedented view of the Sun's corona as it progressively dips closer into the solar atmosphere with each solar encounter. Each set of observations provides a unique opportunity to test and…