The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform
Sanket K Solanki - One of the best experts on this subject based on the ideXlab platform.
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The magnetic field in the Solar Atmosphere
Astronomy and Astrophysics Review, 2014Co-Authors: Thomas Wiegelmann, J. K. Thalmann, Sanket K SolankiAbstract:This publication provides an overview of magnetic fields in the Solar Atmosphere with the focus lying on the corona. The Solar magnetic field couples the Solar interior with the visible surface of the Sun and with its Atmosphere. It is also responsible for all Solar activity in its numerous manifestations. Thus, dynamic phenomena such as coronal mass ejections and flares are magnetically driven. In addition, the field also plays a crucial role in heating the Solar chromosphere and corona as well as in accelerating the Solar wind. Our main emphasis is the magnetic field in the upper Solar Atmosphere so that photospheric and chromospheric magnetic structures are mainly discussed where relevant for higher Solar layers. Also, the discussion of the Solar Atmosphere and activity is limited to those topics of direct relevance to the magnetic field. After giving a brief overview about the Solar magnetic field in general and its global structure, we discuss in more detail the magnetic field in active regions, the quiet Sun and coronal holes.
J. C. Vial - One of the best experts on this subject based on the ideXlab platform.
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Turbulence in the Solar Atmosphere and Solar Wind
Space Science Reviews, 2010Co-Authors: A. Petrosyan, B. Roberts, A. Balogh, M. L. Goldstein, J. Léorat, E. Marsch, K. Petrovay, R. Steiger, J. C. VialAbstract:The objective of this review article is to critically analyze turbulence and its role in the Solar Atmosphere and Solar wind, as well as to provide a tutorial overview of topics worth clarification. Although turbulence is a ubiquitous phenomenon in the sun and its heliosphere, many open questions exist concerning the physical mechanisms of turbulence generation in Solar environment. Also, the spatial and temporal evolution of the turbulence in the Solar Atmosphere and Solar wind are still poorly understood. We limit the scope of this paper (leaving out the Solar interior and convection zone) to the magnetized plasma that reaches from the photosphere and chromosphere upwards to the corona and inner heliosphere, and place particular emphasis on the magnetic field structures and fluctuations and their role in the dynamics and radiation of the coronal plasma. To attract the attention of scientists from both the fluid-dynamics and space-science communities we give in the first two sections a phenomenological overview of turbulence-related processes, in the context of Solar and heliospheric physics and with emphasis on the photosphere-corona connection and the coupling between the Solar corona and Solar wind. We also discuss the basic tools and standard concepts for the empirical analysis and theoretical description of turbulence. The last two sections of this paper give a concise review of selected aspects of oscillations and waves in the Solar Atmosphere and related fluctuations in the Solar wind. We conclude with some recommendations and suggest topics for future research.
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Turbulence in the Solar Atmosphere and Solar Wind
Space Science Reviews, 2010Co-Authors: A. Petrosyan, B. Roberts, A. Balogh, M. L. Goldstein, J. Léorat, E. Marsch, K. Petrovay, R. Von Steiger, J. C. VialAbstract:The objective of this review article is to critically analyze turbulence and its role in the Solar Atmosphere and Solar wind, as well as to provide a tutorial overview of topics worth clarification. Although turbulence is a ubiquitous phenomenon in the sun and its heliosphere, many open questions exist concerning the physical mechanisms of turbulence generation in Solar environment. Also, the spatial and temporal evolution of the turbulence in the Solar Atmosphere and Solar wind are still poorly understood. We limit the scope of this paper (leaving out the Solar interior and convection zone) to the magnetized plasma that reaches from the photosphere and chromosphere upwards to the corona and inner heliosphere, and place particular emphasis on the magnetic field structures and fluctuations and their role in the dynamics and radiation of the coronal plasma. To attract the attention of scientists from both the fluid-dynamics and space-science communities we give in the first two sections a phenomenological overview of turbulence-related processes, in the context of Solar and heliospheric physics and with emphasis on the photosphere-corona connection and the coupling between the Solar corona and Solar wind. We also discuss the basic tools and standard concepts for the empirical analysis and theoretical description of turbulence. The last two sections of this paper give a concise review of selected aspects of oscillations and waves in the Solar Atmosphere and related fluctuations in the Solar wind. We conclude with some recommendations and suggest topics for future research.
Thomas Wiegelmann - One of the best experts on this subject based on the ideXlab platform.
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The magnetic field in the Solar Atmosphere
Astronomy and Astrophysics Review, 2014Co-Authors: Thomas Wiegelmann, J. K. Thalmann, Sanket K SolankiAbstract:This publication provides an overview of magnetic fields in the Solar Atmosphere with the focus lying on the corona. The Solar magnetic field couples the Solar interior with the visible surface of the Sun and with its Atmosphere. It is also responsible for all Solar activity in its numerous manifestations. Thus, dynamic phenomena such as coronal mass ejections and flares are magnetically driven. In addition, the field also plays a crucial role in heating the Solar chromosphere and corona as well as in accelerating the Solar wind. Our main emphasis is the magnetic field in the upper Solar Atmosphere so that photospheric and chromospheric magnetic structures are mainly discussed where relevant for higher Solar layers. Also, the discussion of the Solar Atmosphere and activity is limited to those topics of direct relevance to the magnetic field. After giving a brief overview about the Solar magnetic field in general and its global structure, we discuss in more detail the magnetic field in active regions, the quiet Sun and coronal holes.
Lidong Xia - One of the best experts on this subject based on the ideXlab platform.
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Upflows in the upper Solar Atmosphere
Solar Physics, 2021Co-Authors: Hui Tian, Louise K. Harra, Deborah Baker, David H. Brooks, Lidong XiaAbstract:Spectroscopic observations at extreme and far ultraviolet wavelengths have revealed systematic upflows in the Solar transition region and corona. These upflows are best seen in the network structures of the quiet Sun and coronal holes, boundaries of active regions, and dimming regions associated with coronal mass ejections. They have been intensively studied in the past two decades because they are highly likely to be closely related to the formation of the Solar wind and heating of the upper Solar Atmosphere. We present an overview of the characteristics of these upflows, introduce their possible formation mechanisms, and discuss their potential roles in the mass and energy transport in the Solar Atmosphere. Though past investigations have greatly improved our understanding of these upflows, they have left us with several outstanding questions and unresolved issues that should be addressed in the future. New observations from the Solar Orbiter mission, the Daniel K. Inouye Solar Telescope and the Parker Solar Probe will likely provide critical information to advance our understanding of the generation, propagation and energization of these upflows.
J.-c. Henoux - One of the best experts on this subject based on the ideXlab platform.
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Return current losses in pulse beam heating of the Solar Atmosphere
Astronomy and Astrophysics, 1992Co-Authors: M. Karlicky, J.-c. HenouxAbstract:The influence of return current losses on pulse beam heating of the Solar Atmosphere is studied using a 1D-hybrid code. While heating of the coronal plasma by the penetrating electron beam is obtained as expected, strong return current losses of beam electrons at the resistivity jump in the transition region are also found. The electron beam energy is deposited at greater heights in the Solar Atmosphere than in the case of pure collisional losses. At the starting time of the flare, due to a strong return current heating, a very steep transition region is formed where upwards and downwards plasma flows are generated. However, this state has a transitory character
