scholarly journals Dynamics of interplanetary CMEs and associated type II bursts

2008 ◽  
Vol 4 (S257) ◽  
pp. 287-290 ◽  
Author(s):  
Alejandro Lara ◽  
Andrea I. Borgazzi
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Large Scale ◽  
Interplanetary Medium ◽  
Hydrodynamic Theory ◽  
Type Ii ◽  
Large Scale Structures ◽  
Scale Structures ◽  
Ambient Solar Wind ◽  
Inner Heliosphere

AbstractCoronal mass ejections (CMEs) are large scale structures of plasma (~1016g) and magnetic field expelled from the solar corona to the interplanetary medium. During their travel in the inner heliosphere, these “interplanetary CMEs” (ICMEs), suffer acceleration due to the interaction with the ambient solar wind. Based on hydrodynamic theory, we have developed an analytical model for the ICME transport which reproduce well the observed deceleration of fast ICMEs. In this work we present the results of the model and its application to the CME observed on May 13, 2005 and the associated interplanetary type II burst.

The Hilbert-Huang Transform (HHT) as a tool for characterizing dynamical features of Mercury’s and Venus’ magnetospheres

2020 ◽  
Author(s):  
Tommaso Alberti ◽  
Anna Milillo ◽  
Monica Laurenza ◽  
Stefano Massetti ◽  
Stavro Ivanovski ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Large Scale ◽  
Global Features ◽  
Hilbert Huang Transform ◽  
Ulf Wave ◽  
Local And Global Features ◽  
Spatio Temporal ◽  
Planetary Magnetic Field ◽  
Ambient Solar Wind

<p class="western" align="justify"><span>The interaction between the interplanetary medium and planetary environments gives rise to different phenomena according to the spatio-temporal scales. Here we apply for the first time a novel data analysis method, i.e., the Hilbert-Huang Transform, to discriminate both local and global properties of Venus’ and Mercury’s environments as seen during two MESSENGER flybys. Hence, we may infer that the near-Venus environment is similar in terms of local and global features to the ambient solar wind, possibly related to the induced nature of Venus’ magnetosphere. Conversely, the near-Mercury environment presents some different local features with respect to the ambient solar wind, due to both interaction processes and intrinsic structures of the Hermean environment. Our findings support the ion kinetic nature of the Hermean plasma structures, with the foreshock and the magnetosheath regions being characterized by inhomogeneous ion-kinetic intermittent fluctuations, together with MHD and large-scale fluctuations, the latter being representative of the main structure of the magnetosphere. We also show that the HHT analysis allow to capture and reproduce some interesting features of the Hermean environment as flux transfer events, Kelvin-Helmholtz vortex, and ULF wave activity, thus providing a suitable method for characterizing physical processes of different nature. Our approach demonstrate to be very promising for the characterization of the structure and dynamics of planetary magnetic field at different scales, for the identification of different planetary regions, and for the detection of the “effective” planetary magnetic field that can be used for modelling purposes.</span></p>

scholarly journals Solar wind ion trends and signatures: STEREO PLASTIC observations approaching solar minimum

2009 ◽  
Vol 27 (10) ◽  
pp. 3909-3922 ◽  
Author(s):  
A. B. Galvin ◽  
M. A. Popecki ◽  
K. D. C. Simunac ◽  
L. M. Kistler ◽  
L. Ellis ◽  
...  
Keyword(s):  
Solar Wind ◽  
Solar Minimum ◽  
Large Scale ◽  
Slow Solar Wind ◽  
Transient Event ◽  
Large Scale Structures ◽  
Close Proximity ◽  
Scale Structures

Abstract. STEREO has now completed the first two years of its mission, moving from close proximity to Earth in 2006/2007 to more than 50 degrees longitudinal separation from Earth in 2009. During this time, several large-scale structures have been observed in situ. Given the prevailing solar minimum conditions, these structures have been predominantly coronal hole-associated solar wind, slow solar wind, their interfaces, and the occasional transient event. In this paper, we extend earlier solar wind composition studies into the current solar minimum using high-resolution (1-h) sampling times for the charge state analysis. We examine 2-year trends for iron charge states and solar wind proton speeds, and present a case study of Carrington Rotation 2064 (December 2007) which includes minor ion (He, Fe, O) kinetic and Fe composition parameters in comparison with proton and magnetic field signatures at large-scale structures observed during this interval.

Dynamics of helium abundance in magnetic clouds

2021 ◽  
Author(s):  
Alexander Khokhlachev ◽  
Maria Riazantseva ◽  
Liudmila Rakhmanova ◽  
Yuri Yermolaev ◽  
Irina Lodkina
Keyword(s):  
Solar Wind ◽  
Relative Abundance ◽  
Large Scale ◽  
Magnetic Cloud ◽  
Magnetic Clouds ◽  
Helium Abundance ◽  
Local Correlation ◽  
Plasma Parameters ◽  
Large Scale Structures ◽  
Scale Structures

<p>Helium is the second most abundant ion component of the solar wind. The relative abundance of helium can differ significantly in various large-scale structures of the solar wind generated by the nonstationarity and inhomogeneity of the solar corona. For example the helium abundance is ~3% in slow streams and ~4% in fast streams. The maximum helium abundance is usually observed inside magnetic clouds and can reach >10%. The relative abundance of helium can also dynamically vary inside large-scale structures, which can be the result of local processes in plasma.</p><p> In magnetic clouds, the distribution of the helium abundance has an axisymmetric peak with a maximum in the central region of the magnetic cloud, where the ion current flows [Yermolaev et al., 2020]. This research examines the different-scale dynamics of the relative abundance of helium in magnetic clouds. For this purpose, the dependences of the helium abundance on some plasma parameters were studied on different datasets of the OMNI database from 1976 to 2018. It is shown that the helium abundance increases with an increase in the modulus of the interplanetary magnetic field B and with a decrease in the proton plasma parameter β in the center of the magnetic cloud. The scale of this region is ~1 million kilometers. Similar relations of the helium abundance to interplanetary magnetic field direction angles and other solar wind parameters were studied.</p><p>In addition, the work studied intermediate-scale changes (at scale <1 hour) in helium abundance inside magnetic clouds and compression regions in front of them in comparison with other large-scale wind types. For this aim, a correlation analysis of the time series of density and relative abundance of helium was carried out on base of measurements on SPEKTR-R and WIND spacecraft located at a considerable distance from each other. The dependences of the local correlation coefficients (at scale ~1 hour or less) between measurements at two points on the solar wind plasma parameters are considered. Meanwhile these dependencies are compared with the same for other types of solar wind. It is shown that the median values of the local correlation coefficient in the regions of compressed plasma ahead of magnetic clouds exceed the values in other types of wind by about 15%. In addition, the local correlation coefficient increases with an increase in the amplitude of fluctuations of the investigated parameter and the proton velocity. Thus, intermediate-scale fluctuations in the relative helium abundance observed in these structures are quite stable and apparently are formed in the corona acceleration region and then propagate without changes.<br>The work is supported by <span>RFBR grant № <span>19-02-00177</span>a.</span></p><p>References.<br>Yermolaev, Y.I. et al., Dynamics of large-scale solar-wind streams obtained by the double superposed epoch analysis. 4. Helium abundance, Journal of Geophysical Research, 125 (7) DOI: 10.1029/2020JA027878</p>

scholarly journals EUHFORIA: European heliospheric forecasting information asset

2018 ◽  
Vol 8 ◽  
pp. A35 ◽  
Author(s):  
Jens Pomoell ◽  
S. Poedts
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Large Scale ◽  
Weather Forecasting ◽  
Mass Density ◽  
Solar Wind Speed ◽  
Plasma Parameters ◽  
Cone Model ◽  
Plasma State ◽  
Inner Heliosphere

The implementation and first results of the new space weather forecasting-targeted inner heliosphere model “European heliospheric forecasting information asset” (EUHFORIA) are presented. EUHFORIA consists of two major components: a coronal model and a heliosphere model including coronal mass ejections. The coronal model provides data-driven solar wind plasma parameters at 0.1 AU by constructing a magnetic field model of the coronal large-scale magnetic field and employing empirical relations to determine the plasma state such as the solar wind speed and mass density. These are then used as boundary conditions to drive a three-dimensional time-dependent magnetohydrodynamics model of the inner heliosphere up to 2 AU. CMEs are injected into the ambient solar wind modeled using the cone model, with their parameters obtained from fits to imaging observations. In addition to detailing the modeling methodology, an initial validation run is presented. The results feature a highly dynamic heliosphere that the model is able to capture in good agreement with in situ observations. Finally, future horizons for the model are outlined.

Some comments about observations and image processing of comet 29P/Schwassmann-Wachmann 1

1999 ◽  
Vol 173 ◽  
pp. 243-248
Author(s):  
D. Kubáček ◽  
A. Galád ◽  
A. Pravda
Keyword(s):  
Image Processing ◽  
Large Scale ◽  
Harvard College ◽  
Oak Ridge ◽  
Large Scale Structures ◽  
Short Period Comet ◽  
Short Period ◽  
Scale Structures ◽  
Harvard College Observatory ◽  
Period Comet

AbstractUnusual short-period comet 29P/Schwassmann-Wachmann 1 inspired many observers to explain its unpredictable outbursts. In this paper large scale structures and features from the inner part of the coma in time periods around outbursts are studied. CCD images were taken at Whipple Observatory, Mt. Hopkins, in 1989 and at Astronomical Observatory, Modra, from 1995 to 1998. Photographic plates of the comet were taken at Harvard College Observatory, Oak Ridge, from 1974 to 1982. The latter were digitized at first to apply the same techniques of image processing for optimizing the visibility of features in the coma during outbursts. Outbursts and coma structures show various shapes.

scholarly journals The organization and control of an evolving interdependent population

2015 ◽  
Vol 12 (108) ◽  
pp. 20150044 ◽  
Author(s):  
Dervis C. Vural ◽  
Alexander Isakov ◽  
L. Mahadevan
Keyword(s):  
Evolutionary Game Theory ◽  
Large Scale ◽  
Social Evolution ◽  
Evolutionary Game ◽  
Large Scale Structures ◽  
External Perturbations ◽  
Emergence Of Cooperation ◽  
Scale Structures ◽  
And Control ◽  
Evolutionarily Stable

Starting with Darwin, biologists have asked how populations evolve from a low fitness state that is evolutionarily stable to a high fitness state that is not. Specifically of interest is the emergence of cooperation and multicellularity where the fitness of individuals often appears in conflict with that of the population. Theories of social evolution and evolutionary game theory have produced a number of fruitful results employing two-state two-body frameworks. In this study, we depart from this tradition and instead consider a multi-player, multi-state evolutionary game, in which the fitness of an agent is determined by its relationship to an arbitrary number of other agents. We show that populations organize themselves in one of four distinct phases of interdependence depending on one parameter, selection strength. Some of these phases involve the formation of specialized large-scale structures. We then describe how the evolution of independence can be manipulated through various external perturbations.

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