On the effects of dynamical turbulence on the perpendicular diffusion of low-energy cosmic ray electrons

Diffusion perpendicular to the heliospheric magnetic field plays an integral role in the transport of charged particles in the heliosphere. In this study the perpendicular diffusion coefficient of low-energy cosmic ray electrons is calculated, using an equation derived from the random ballistic decorrelation interpretation of nonlinear guiding centre theory. An observationally motivated 2D turbulence power spectrum is assumed and the effects of various turbulence inputs on the resulting perpendicular diffusion coefficient are investigated. The perpendicular diffusion coefficients are first determined at 1 AU, for both magnetostatic and dynamical turbulence conditions. These solutions are also evaluated for radial distances of 0.1 AU to 10 AU to further investigate the values of the perpendicular diffusion coefficients in the very inner heliosphere. The results of this study show that the dissipation range of the turbulence power spectrum provides a negligible contribution towards the perpendicular diffusion coefficient, and that solutions derived using only the energy containing range serve as good approximations for solutions derived assuming the full 2D turbulence power spectrum. Finally, it is shown that the effects of dynamical turbulence, as considered in the present study, do not affect the perpendicular diffusion coefficients derived from the scattering theory considered here.     

27-day variations of the galactic cosmic ray intensity and anisotropy in the minimum of the 23rd solar activity cycle

We study the 27-day variations of the solar wind velocity, galactic cosmic ray (GCR) intensity and anisotropy in the last minimum epoch of solar activity (2007–2009, A < 0). The average amplitude of the 27-day variation of the galactic cosmic ray anisotropy (A27A) in the current minimum epoch of solar activity (2007–2009, A < 0) is lesser than in previous positive polarity period as it is expected from the drift theory. So, polarity dependence rule for the 27-day variation of the GCR anisotropy is fully kept. It is a universal principle for the amplitudes of the 27-day variation of the GCR anisotropy. At the same time, the average amplitude of the 27-day variation of the GCR intensity (A27I) remains at the same level as for previous minimum epoch 1995–1997 (A > 0) showing by the same token an violation of its polarity dependence rule established earlier. We assume that this phenomenon could be generally related with the well established 27-day variation of the solar wind velocity being in anti-correlation with the similar changes of the 27-day variation of the GCR intensity. Generally, a character of the heliolongitudinal asymmetry of spatial large-scale structure of the solar wind velocity (SWV) established in the recent minimum epoch, preferentially pronounces in the behavior of the 27-day variation of the GCR intensity than anisotropy. The formation of the 27-day variation of the GCR anisotropy preferentially takes place in a restricted disk like local vicinity in the helioequatorial region, whilst the 27-day variation of the GCR intensity is formed in the global three dimensional vicinity of the heliosphere.     

Modeling and experimental study of the 27-day variation of galactic cosmic-ray intensity for a solar wind velocity depending on heliolongitude

We develop a three-dimensional (3-D) model of the 27-day variation of galactic cosmic-ray (GCR) intensity with a spatial variation of the solar wind velocity. A consistent, divergence-free interplanetary magnetic field is derived by solving the corresponding Maxwell equations with a variable solar wind speed, which reproduces in situ observed experimental data for the time interval to be analyzed (24 August 2007–28 February 2008). We perform model calculations for the GCR intensity using the variable solar wind and the corresponding magnetic field. Results are compatible with experimental data; the correlation coefficient between our model predictions and observed 27-day GCR variation is 0.80 ± 0.05.     

Power-law spectra of energetic electrons in solar flares from the maximum entropy and dimensional considerations

The maximum entropy formalism and dimensional analysis are used to derive a power-law spectrum of accelerated electrons in impulsive solar flares, where the particles can contain a significant fraction of the total flare energy. Entropy considerations are used to derive a power-law spectrum for a particle distribution characterised by its order of magnitude of energy. The derivation extends an earlier one-dimensional argument to the case of an isotropic three-dimensional particle distribution. Dimensional arguments employ the idea that the spectrum should reflect a balance between the processes of energy input into the corona and energy dissipation in solar flares. The governing parameters are suggested on theoretical grounds and shown to be consistent with solar flare observations. The flare electron flux, differential in the non-relativistic electron kinetic energy E, is predicted to scale as $E^{-3}$. This scaling is in agreement with RHESSI measurements of the hard X-ray flux that is generated by deka-keV electrons, accelerated in intense solar flares.     

Effects of geomagnetic activity and atmospheric power variations on quantitative measures of brain activity: Replication of the Azerbaijani studies

This study replicates and extends the observations by Babayev and Allahveriyeva that changes in right hemispheric electroencephalographic activity are correlated with increases in geomagnetic activity. During the geomagnetically quiet interface between solar cycle 23 and 24 quantitative electroencephalographic (QEEG) measurements were completed for normal young adults in three separate experiments involving about 120 samples over 1.5 years. The most consistent, moderate strength correlations occurred for the changes in power within the gamma and theta ranges over the right frontal lobe. Real-time measures of atmospheric power obtained from polar orbiting satellites showed similar effects. The preferential involvement of the right frontal lobe and the regions subject to its inhibition with environmental energetic changes are consistent with the behavioural correlations historically associated with these conditions. They include increased incidence of emotional lability, erroneous reconstruction of experiences, social confrontations, and unusual perceptions.     

Effects of geomagnetic activity variations on the physiological and psychological state of functionally healthy humans: Some results of Azerbaijani studies

There are collaborative and cross-disciplinary space weather studies in the Azerbaijan National Academy of Sciences conducted with purposes of revealing possible effects of solar, geomagnetic and cosmic ray variability on certain technological, biological and ecological systems. This paper describes some results of the experimental studies of influence of the periodical and aperiodical changes of geomagnetic activity upon human brain, human health and psycho-emotional state. It also covers the conclusions of studies on influence of violent solar events and severe geomagnetic storms of the solar cycle 23 on the mentioned systems in middle-latitude location. It is experimentally established that weak and moderate geomagnetic storms do not cause significant changes in the brain’s bioelectrical activity and exert only stimulating influence while severe disturbances of geomagnetic conditions cause negative influence, seriously disintegrate brain’s functionality, activate braking processes and amplify the negative emotional background of an individual. It is concluded that geomagnetic disturbances affect mainly emotional and vegetative spheres of human beings while characteristics reflecting personality properties do not undergo significant changes.