The Differential Solar Rotation

1994 ◽  
pp. 27-47
Author(s):  
Günther Rüdiger ◽  
Leonid L. Kitchatinov
Keyword(s):  
Solar Rotation

Influence of Magnetic Fields on Solar Hydrodynamics: Experimental Results

1977 ◽  
Vol 36 ◽  
pp. 143-180 ◽  
Author(s):  
J.O. Stenflo
Keyword(s):  
Solar Activity ◽  
Energy Balance ◽  
Magnetic Fields ◽  
Solar Atmosphere ◽  
General Problem ◽  
Solar Rotation ◽  
Active Regions ◽  
Physical Conditions ◽  
Dynamic Phenomena

It is well-known that solar activity is basically caused by the Interaction of magnetic fields with convection and solar rotation, resulting in a great variety of dynamic phenomena, like flares, surges, sunspots, prominences, etc. Many conferences have been devoted to solar activity, including the role of magnetic fields. Similar attention has not been paid to the role of magnetic fields for the overall dynamics and energy balance of the solar atmosphere, related to the general problem of chromospheric and coronal heating. To penetrate this problem we have to focus our attention more on the physical conditions in the ‘quiet’ regions than on the conspicuous phenomena in active regions.

scholarly journals Solar rotation effects on the Martian ionosphere

2014 ◽  
Vol 119 (8) ◽  
pp. 6612-6622 ◽  
Author(s):  
N. Venkateswara Rao ◽  
N. Balan ◽  
A. K. Patra
Keyword(s):  
Solar Rotation ◽  
Martian Ionosphere

scholarly journals Time Dependence of the Solar Rotation Rate

2021 ◽  
Author(s):  
Roger Ulrich ◽  
John Boyden ◽  
Tham Tran ◽  
Luca Bertello
Keyword(s):  
Time Dependence ◽  
Rotation Rate ◽  
Solar Rotation ◽  
Solar Rotation Rate

Solar rotation and the giant cells

Solar Physics ◽  
1987 ◽  
Vol 110 (1) ◽  
pp. 59-71 ◽  
Author(s):  
P. R. Wilson
Keyword(s):  
Solar Rotation ◽  
Giant Cells

scholarly journals The 30 cm radio flux as a solar proxy for thermosphere density modelling

2017 ◽  
Vol 7 ◽  
pp. A9 ◽  
Author(s):  
Thierry Dudok de Wit ◽  
Sean Bruinsma
Keyword(s):  
Solar Rotation ◽  
Rotation Period ◽  
Density Variation ◽  
Temperature Model ◽  
Radio Flux ◽  
Model Bias ◽  
Solar Forcing ◽  
Radio Emissions ◽  
Solar Uv ◽  
Density Modelling

The 10.7 cm radio flux (F10.7) is widely used as a proxy for solar UV forcing of the upper atmosphere. However, radio emissions at other centimetric wavelengths have been routinely monitored since the 1950 s, thereby offering prospects for building proxies that may be better tailored to space weather needs. Here we advocate the 30 cm flux (F30) as a proxy that is more sensitive than F10.7 to longer wavelengths in the UV and show that it improves the response of the thermospheric density to solar forcing, as modelled with DTM (Drag Temperature Model). In particular, the model bias drops on average by 0–20% when replacing F10.7 by F30; it is also more stable (the standard deviation of the bias is 15–40% smaller) and the density variation at the the solar rotation period is reproduced with a 35–50% smaller error. We compare F30 to other solar proxies and discuss its assets and limitations.

Global coronal and heliospheric magnetic field modelling for Solar Orbiter

2021 ◽  
Author(s):  
Thomas Wiegelmann ◽  
Thomas Neukirch ◽  
Iulia Chifu ◽  
Bernd Inhester
Keyword(s):  
Magnetic Field ◽  
Solar Rotation ◽  
Coronal Magnetic Field ◽  
Important Research ◽  
Parker Spiral ◽  
Important Research Topic ◽  
Mhd Equilibria ◽  
Solar Wind Flow ◽  
Nonlinear Force

<p>Computing the solar coronal magnetic field and plasma<br>environment is an important research topic on it's own right<br>and also important for space missions like Solar Orbiter to<br>guide the analysis of remote sensing and in-situ instruments.<br>In the inner solar corona plasma forces can be neglected and<br>the field is modelled under the assumption of a vanishing<br>Lorentz-force. Further outwards (above about two solar radii)<br>plasma forces and the solar wind flow has to be considered.<br>Finally in the heliosphere one has to consider that the Sun<br>is rotating and the well known Parker-spiral forms.<br>We have developed codes based on optimization principles<br>to solve nonlinear force-free, magneto-hydro-static and<br>stationary MHD-equilibria. In the present work we want to<br>extend these methods by taking the solar rotation into account.</p>

scholarly journals Measuring planetary atmospheric dynamics with Doppler spectroscopy

2018 ◽  
Vol 617 ◽  
pp. A41 ◽  
Author(s):  
Patrick Gaulme ◽  
François-Xavier Schmider ◽  
Ivan Gonçalves
Keyword(s):  
Radial Velocity ◽  
Solar Rotation ◽  
Imaging Spectroscopy ◽  
Planetary Atmospheres ◽  
Atmospheric Dynamics ◽  
Doppler Imaging ◽  
Significant Difference ◽  
Doppler Spectroscopy ◽  
The Impact ◽  
Cloud Tracking

Doppler imaging spectroscopy is the most reliable method of directly measuring wind speeds of planetary atmospheres of the solar system. However, most knowledge about atmospheric dynamics has been obtained with cloud-tracking technique, which consists of tracking visible features from images taken at different dates. Doppler imaging is as challenging (motions can be less than 100 m s−1) as it is appealing because it measures the speed of cloud particles instead of large cloud structures. A significant difference between wind speed measured by cloud-tracking and Doppler spectroscopy is expected in case of atmospheric waves interfering with cloud structures. The purpose of this paper is to provide a theoretical basis for conducting accurate Doppler measurements of planetary atmospheres, especially from the ground with reflected solar absorption lines. We focus on three aspects which lead to significant biases. Firstly, we fully review the Young effect, which is an artificial radial velocity field caused by the solar rotation that mimics a retrograde planetary rotation. Secondly, we extensively study the impact of atmospheric seeing and show that it modifies the apparent location of the planet in the sky whenever the planet is not observed at full phase (opposition). Moreover, the seeing convolves regions of variable radial velocity and photometry, which biases radial-velocity measurements, by reducing the apparent amplitude of atmospheric motions. Finally, we propose a method to interpret the data: how to retrieve zonal, meridional, vertical, and subsolar-to-antisolar circulation from radial velocity maps, by optimizing the signal-to-noise ratio.

scholarly journals Consistent long-term variation in the hemispheric asymmetry of solar rotation

2013 ◽  
Vol 552 ◽  
pp. A84 ◽  
Author(s):  
L. Zhang ◽  
K. Mursula ◽  
I. Usoskin
Keyword(s):  
Hemispheric Asymmetry ◽  
Solar Rotation ◽  
Term Variation
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