Magnetic Turbulence in the Solar Wind and the Earth's Plasma Sheet

Proceedings of the International Astronomical Union, 2004

In this paper we compare the intermittence properties of magnetic fluctuations (non-Gaussian shape of probability density functions) observed in the solar wind (ACE) with the simultaneous occurrence of intermittence in the Earth's plasma sheet (GEOTAIL). Intervals with different level of magnetic turbulence are investigated separately.

Journal of Atmospheric and Solar-Terrestrial Physics, 2011

The solar wind-magnetosphere coupled system is characterized by dynamical processes. Recent works have shown that nonlinear couplings and turbulence might play a key role in the study of solar wind-magnetosphere interaction processes.

Earth Moon and Planets, 2009

Recent spacecraft observations of magnetic turbulence in the ion foreshock, in the magnetosheath, in the polar cusp regions, and in the magnetotail will be reviewed. Turbulence features like the fluctuation level, the spectral power law index, the turbulence anisotropy and intermittency, and the turbulence driver will be addressed.

Nonlinear Processes in Geophysics, 2008

The importance of space weather and its forecasting is growing as interest in studying geoeffective processes in the Sun-solar wind-magnetosphere-ionosphere coupled system is increasing. This paper introduces the proper selection criteria for solar wind magnetic turbulence events during duskward electric field and southward B z driven geomagnetic storms. Two measures for the strength of solar wind fluctuations were investigated: the standard deviations of magnetic field components and a proxy for the so-called Shebalin anisotropy angles. These measures were compared to the strength of geomagnetic storms obtained from a SYM-H index time series. We found a weak correlation between standard deviation of interplanetary magnetic field GSM component B z and SYM-H index, and a strong correlation between Shebalin anisotropy angle and the SYM-H index, which can be the result of an increase of probability of magnetic reconnection in fluctuating magnetic fields.

Open Journal of Applied Sciences, 2023

Highly turbulent environment, the solar wind is a stream of very energetic particles mainly made of protons and electrons. During its trip in the interplanetary space, this solar flow becomes more accelerated during the outer minima (descending phases) of the solar cycles and can therefore influence all of humanity and its technology. These disturbances lead to socio-economic consequences requiring a precise knowledge of the climate variability. Using a statistical approach, we evaluate the response of the Earth’s magnetosphere to the High-Speed Solar Winds (HSSW) forcing during the peaks of the last five outer minima. To do so, 1UA data of solar wind and magnetic field parameters were extracted from OMNI browser. Analysis of the energetic solar plasma particles shows that strong geomagnetic field variations can occur even in the absence of large solar disturbances. While the normalized reconnection rate was estimated to be ~21% of the total variance of the magnetospheric variables, the upstream of the magnetic cavity was perturbed 80% of the time with large energies recorded. As a result, Earth’s magnetosphere becomes denser (i.e., more drag), which is a problem for spacecraft. Thus, the coupled solar wind-magnetosphere system follows scale-invariant dynamics and is in a state far from equilibrium. Our analysis provides insight into the main cause of geomagnetic storms with more than 97% of HSSW imposed in the range 300 - 850 km/s. These high-speeds lead to auroras that can disrupt electrical and communication systems.

Proceedings of the International Astronomical Union, 2009

We apply two nonlinear techniques, kurtosis and phase coherence index, to analyze magnetic field measurements from SOHO MDI solar images, ACE and Cluster data in the solar wind, and ground magnetometers in Brazil. We focus on two events: a non-ICME event in February 2002 and an ICME event in January 2005. Finite degree of non-Gaussianity and phase synchronization are observed in all datasets. The nonlinear response of the Earth's geomagnetic field to an ICME event in the solar wind is discussed.

Magnetic turbulence is found in most space plasmas, including the geospace environment. Recent spacecraft observations of magnetic turbulence in the ion foreshock, in the magnetosheath, in the polar cusp regions, and in the magnetotail will be reviewed. Turbulence features like the fluctuation level, the spectral power law index, the turbulence anisotropy and intermittency, and the turbulence driver will be addressed. The influence of such a turbulence on the plasma transport and dynamics will be described, also using the results of numerical simulations.

Proceedings of The 34th International Cosmic Ray Conference — PoS(ICRC2015), 2016

Data of By, Bz components of the interplanetary magnetic field (IMF) have been used to study a features of the IMF turbulences for two positive (A>0) and two negative (A<0) polarities epoch of solar magnetic cycles (1969-2011). We found that the changes of the exponents vy, νz, of the power spectral density (PSD) of the By, Bz, components shows a radical alternation of the large-scale structure of the IMF turbulence. It was also found a distinction between the temporal changes of the exponents vy, νz, for the A>0 and the A<0 polarity epoch of solar magnetic cycles, especially in minima and near minima epoch of solar activity. We suppose that the changes of the turbulence in the range of frequencies (10-6-10-5) Hz (responsible for the scattering of the GCR particles of the energy 5-50 GeV) and the module of the IMF versus solar activity can be considered as the general reasons of the long period variations of the GCR intensity. Rigidity spectrum of the long period variations of the GCR intensity is soft in positive A> 0 polarity epochs, than in negative A<0 epochs.

https://journals.openedition.org/mefra/9191

The Roman figurative calendars, in particular the mosaics of months, are concentrated from the second to the seventh century A.D. especially in Italy, North Africa, Greece and Arabia. Their main characteristic is the representation of the twelve months of the year referable to three iconographic themes: the festive, the astrological, and the rural types. The first one includes the images of months that allude to the most important religious festivals, such as Compitalia in January and Lupercalia in February. The aim of this paper is to demonstrate that the iconography of these two months has been developed in the Augustan age. This hypothesis is based on the fact that the intervention of Augustus on the temporal dimension was very important, because he has used the calendar as a political mean, by adding numerous feriae regarding to him, and he has reformed some ancient festivals, like above mentioned Compitalia and Lupercalia, in order to legitimize ideologically his power.