The Forbush effects associated with far western and eastern powerful sources on the Sun that occurred on the background of unsettled and moderate interplanetary and geomagnetic disturbances have been studied by data from neutron monitor networks and relevant measurements of the solar wind parameters. These Forbush effects may be referred to a special sub-class of events, with the characteristics like the event in July 2005, and incorporated by the common conditions: absence of a significant disturbance in the Earth vicinity; absence of a strong geomagnetic storm; slow decrease of cosmic ray intensity during the main phase of the Forbush effect. General features and separate properties in behavior of density and anisotropy of 10 GV cosmic rays for this subclass are investigated.

In situ and remote observations indicate that relativistic or ultra relativistic electrons are formed at various magnetized configurations. It is suggested that a specific bootstrap mechanism operates in some of these environments. The mechanism applies to (a) relativistic electrons observed on localized field lines in outer radiation belt - through a process initiated at a distant substorm injection; (b) relativistic electrons observed at the interplanetary medium - through a process initiated via coronal injection, at large distances from flares or propagating CME; (c) ultra-relativistic electrons deduced at the galactic jets - through a process initiated via local injection at the small-scale magnetic field. The injected nonisotropic electrons excite whistler waves which boost efficiently the tail of the electron distribution.

Galactic cosmic rays (GCR) provide information on the solar neighborhood during the sun's motion in the galaxy. There is now considerable evidence for GCR acceleration by shock waves of supernova in active star-forming regions (OB associations) in the galactic spiral arms. During times of passage into star-forming regions increases in the GCR-flux are expected. Recent data from the Spitzer Space Telescope (SST) are shedding light on the structure of the Milky Way and of its star-forming-regions in spiral arms. Records of flux variations may be found in solar system detectors, and iron meteorites with GCR-exposure times of several hundred million years have long been considered to be potential detectors (Voshage, 1962). Variable concentration ratios of GCR-produced stable and radioactive nuclides, with varying half-lives and therefore integration times, were reported by Lavielle et al. (1999), indicating a recent 38% GCR-flux increase. Potential flux recorders consisting of different pairs of nuclides can measure average fluxes over different time scales (Lavielle et al., 2007; Mathew and Marti, 2008). Specific characteristics of two pairs of recorders (81Kr-Kr and 129I-129Xe) are the properties of self-correction for GCR-shielding (flux variability within meteorites of varying sizes). The 81Kr-Kr method (Marti, 1967) is based on Kr isotope ratios, while stable 129Xe is the decay product of the radionuclide 129I, which is produced by secondary neutron reactions on Te in troilites of iron meteorites. The two chronometers provide records of the average GCR flux over 1 and 100 million year time scales, respectively.

Our model generalizes the differential D(E) and integral D(>E) spectra of cosmic rays (CR) during the 11-year solar cycle. The empirical model takes into account galactic (GCR) and anomalous cosmic rays (ACR) heliospheric modulation by four coefficients. The calculated integral spectra in the outer planets are on the basis of mean gradients: for GCR – 3%/AU and 7%/AU for anomalous protons. The obtained integral proton spectra are compared with experimental data, the CRÈME96 model for the Earth and theoretical results of 2D stochastic model. The proposed analytical model gives practical possibility for investigation of experimental data from measurements of galactic cosmic rays and their anomalous component.

We present a study of solar energetic particles (SEPs) in association with coronal mass ejections (CMEs) and type II radio bursts. The particle and CME observations cover the years 1996–2007. We find that heavy-ion events in association with type II bursts and proton events are produced in more western and most energetic CMEs. In addition, the source distribution of type II associated proton events with heavy ions reminds the source distribution expected for events with flare particles. Therefore, the estimation of relative contributions by flares and shocks in SEP events and separation of suggested different particle acceleration models is complicated.

The two Helios probes traveled at variable longitudinal and radial separations through the inner heliosphere. They collected most valuable high resolution plasma and magnetic field data for an entire solar cycle. The mission is still so successful that no other missions will collect the same kind of data in the next 20 years. One of the subjects studied after the success of the Helios mission was the identification of more than 390 shock waves driven by Interplanetary Coronal Mass Ejections (ICMEs). Combining the data from both probes, we make a statistical study for the extension of the shock waves in the interplanetary medium. For longitudinal separations of 90° we found a cutoff value at this angular separation. A shock has 50% of chance to be observed by both probes and the same probability for not being observed by two spacecrafts at the same time, when the angle between them is around 90°. We describe the dependence of the probability for shocks to be observed by both probes with decreasing spacecraft separation. Including plasma data from the ISEE-3 and IMP-8 spacecrafts improves our statistical evaluation substantially.

A numerical simulation with ENLIL+Cone model was carried out to study the propagation of the shock driven by the 2005 May 13 CME. We then conducted a statistical analysis on a subset of similar events, where a decameter-hectometric (DH) type II radio burst and a counterpart kilometric type II have been observed to be associated with each CME (DHkm CME). The simulation results show that fast CME-driven shocks experienced a rapid deceleration as they propagated through the corona and then kept a nearly constant speed traveling out into the heliosphere. Two improved methods are proposed to predict the fast CME-driven shock arrival time, which give the prediction errors of 3.43 and 6.83 hrs, respectively.

We study the MHD processes related to a flare/CME event in the lower solar corona using numerical simulations. Our initial state is an isothermal gravitationally stratified corona with an embedded flux rope magnetic field structure. The eruption is driven by applying an artificial force to the flux rope. The results show that as the flux rope rises, a shock structure is formed, reaching from ahead of the flux rope all the way to the solar surface. The speed of the shock quickly exceeds that of the driving flux rope, and the shock escapes from the driver. Thus, the shock exhibits characteristics both of the driven and blast wave type. In addition, the temperature distribution behind the shock is loop-like, implying that erupting loop-like structures observed in soft X-ray images might be shocks. Finally, we note that care must be taken when performing correlation analysis of the speed and location of type II bursts and ejecta.

External energy inputs into all planetary upper atmospheres (including more than a half dozen moons with atmospheres) are comprised of combinations of solar EUV, soft x-rays, solar energetic particles, solar wind charged particles, magnetospherically accelerated particles, solar wind electric field, interplanetary dust particles as well as propagating lower atmosphere disturbances. Each input has analogous physical interactions with all planetary ionospheres and upper atmospheres, but the integrated consequences of the multiple energy inputs vary from planet to planet. The Earth forms the framework for most fundamental processes because of extensive measurements of the effects of each of the inputs. However the conditions at Earth are far different from those at the carbon dioxide atmosphere of magnetic field-free, slow-rotating Venus, the carbon dioxide atmosphere of Mars with patchy remnant magnetic fields, while the outer planets have hydrogen atmospheres, are fast rotating with intrinsic magnetic fields, and encompass moons that interact with the magnetospheres and have exotic atmospheres. Although the physical processes are known, our understanding of our solar system's ionospheres diminishes with increasing distance from the Sun.

The effects of changes in the solar radiative emission on ozone levels in the stratosphere have been considered as a candidate to explain the link between solar activity and its effects on the climate. As ozone absorbs electromagnetic radiation, changes in ozone concentrations alter Earth's radiative balance by modifying both incoming solar radiation and outgoing radiation. In this way, ozone controls solar energy deposition in the stratosphere and its variations alter the thermal structure of the stratosphere. These changes are assumed to propagate downward through a chain of feedbacks involving thermal and dynamical processes. The effects of high energy particle precipitation on mesospheric and stratospheric ozone have also been investigated. However, while the effects of high energy particle precipitation on ozone distribution in the auroral region has been investigated during the last decades, little is known about the role of the high energy particle precipitation on the stratospheric composition and thermal structure in the tropical/subtropical region. Here we show that the spatial distribution of the lower stratosphere temperature is affected by the presence of the southern hemisphere magnetic anomaly. We found that during the austral winter and spring, in the subtropical region (below 30 deg S), the reduction of the lower stratosphere temperature occurs systematically in the magnetic anomaly area. This result is consistent with the observations that in the southern hemisphere subtropical region the energy of precipitating particles is deposited lower in altitude in regions with weaker magnetic field intensity.

We present unique observations obtained by the Magnetospheric Imaging Instrument (MIMI) on the Cassini spacecraft, of the energetic ion population in the environment upstream from the dawn-to-noon sector of the Kronian magnetosphere during the approach phase and subsequent several orbits of the Cassini spacecraft around the planet. High sensitivity observations of energetic ion directional intensities, energy spectra, and ion composition were obtained by the Ion and Neutral Camera (INCA) of the MIMI instrument complement with a geometry factor of ~2.5 cm2sr. Charge state information was provided by the Charge-Energy-Mass-Spectrometer (CHEMS) over the range ~3 to 220 keV per charge. The observations revealed the presence of distinct upstream bursts of energetic hydrogen and oxygen ions up to distances of ~135 RS. The observations are presented and their theoretical implications are addressed.

Stereographic projection of Hopf field on the 3-sphere into Euclidean 3-space is used as a model of 3D steady flow of ideal compressible fluid in MHD. In such case, flow lines are Villarceau circles lying on tori corresponding to the levels of Bernoulli function. Existence of an optimal torus with minimal relative surface free energy is shown. Beat of oscillations with wave numbers corresponding to structural radii of optimal torus leads to scaling of optimal tori. Spatial intersection of homothetic tori within one torus result in formation of cluster with the size depending on scaling factor. Optimal tori are considered as precursors of planetary orbits.

Modern radio telescopes are extremely sensitive to plasma on the line of sight from a radio source to the antenna. Plasmas in the corona and solar wind produce measurable changes in the radio wave amplitude and phase, and the phase difference between wave fields of opposite circular polarization. Such measurements can be made of radio waves from spacecraft transmitters and extragalactic radio sources, using radio telescopes and spacecraft tracking antennas. Data have been taken at frequencies from about 80 MHz to 8000 MHz. Lower frequencies probe plasma at greater heliocentric distances. Analysis of these data yields information on the plasma density, density fluctuations, and plasma flow speeds in the corona and solar wind, and on the magnetic field in the solar corona. This paper will concentrate on the information that can be obtained from measurements of Faraday rotation through the corona and inner solar wind. The magnitude of Faraday rotation is proportional to the line of sight integral of the plasma density and the line-of-sight component of the magnetic field. Faraday rotation provides an almost unique means of estimating the magnetic field in this part of space. This technique has contributed to measurement of the large scale coronal magnetic field, the properties of electromagnetic turbulence in the corona, possible detection of electrical currents in the corona, and probing of the internal structure of coronal mass ejections (CMEs). This paper concentrates on the search for small-scale coronal turbulence and remote sensing of the structure of CMEs. Future investigations with the Expanded Very Large Array (EVLA) or Murchison Widefield Array (MWA) could provide unique observational input on the astrophysics of CMEs.

The dynamics of fluctuations in a closed coronal structure is regulated both by resonance with motions at bases that stores energy in the structure in form of discrete eigenmodes, and by nonlinear couplings that move this energy along the spectrum to smaller scales. The energy balance is evaluated both analytically and, numerically, using an hybrid shell model. The input energy flux is independent of nonlinear effects and is determined by slow (DC) perturbations. Coherent eigenmode couplings determine the nonlinear energy flux and, consequently, the level of fluctuations at large scales. The estimated velocity fluctuation level is in agreement with measures of nonthermal velocity in corona. The resulting turbulence spectrum contains both a pre-inertial range where coherent interactions dominate, and a standard inertial range where the turbulence behaves as in an unbounded system.

The propagation of Alfvén waves from the photosphere into the corona with regard to the fine structure of the magnetic field is considered. The energy flux of Alfvén–type waves generated in the photosphere by convective motions does not depend on the ionization ratio. The reflection coefficient continuously decreases with a decrease of wave period. Influence of the external magnetic field on the Spruit cutoff frequency for transverse (kink) modes excited in the thin magnetic flux tubes is analyzed. Torsional modes can penetrate into the upper atmosphere most effectively since their amplitudes does not increase with height in the photosphere while kink ones can be transformed into shock waves in the lower chromosphere because of a significant increase of amplitudes. In spite of stratification the linearity of Alfvén–type modes in the chromosphere is conserved due to violation of the WKB approximation. The important role of the magnetic canopy is discussed. Alfvén waves generated by convective motions in the photosphere can contribute significantly to the heating of the coronal plasma in quite regions of the Sun.

The gravitational stratification effect on magnetohydrodynamic waves at a single interface in the solar atmosphere has been studied in the penumbral region of the sunspot recently. The existence of slow and fast magneto acoustic gravity waves and their characteristics has been discussed. The effect of flows on magneto acoustic gravity surface waves leads to modes called flow modes or v-modes. The present geometry is that of a plasma slab moving with uniform velocity surrounded by a plasma of different density. As is applicable to the corona, we assume that the plasma β to be small. The dispersion characteristics change significantly with a change in the value of G (gravity) and uniform flow.

Most treatments of lower hybrid waves include either electromagnetic or warm-plasma effects, but not both. Here we compare numerical dispersion curves for lower hybrid waves with a new analytic dispersion relation that includes both warm and electromagnetic effects. Very good agreement is obtained over significant ranges in wavenumber and plasma parameters, except where ion magnetization effects become important.

The supersonic solar wind is highly variable on all time scales near the Sun but fluctuations are moderated by self-interaction as this plasma moves outward. The solar wind runs into many obstacles on its way out. The neutrals from the interstellar medium slow it down. Magnetospheres and interplanetary coronal mass ejections (ICMEs) cause shocks to form so that the flow can divert around these obstacles. Finally the solar wind is stopped by the circum-heliospheric interstellar medium (CHISM); it slows at the termination shock and then turns down the heliotail. The shocks and sheaths formed by these interactions cover scales which vary by orders of magnitude; some aspects of these shocks and sheaths look very similar and some very different. We discuss solar wind evolution, interaction with the neutrals from the CHISM, foreshocks, shock structure, shock heating, asymmetries, and sheath variability in different sheath regions.

By performing global 1D MHD simulations, we investigate the heating and acceleration of solar and stellar winds in open magnetic field regions. Our simulation covers from photosphere to 20-60 stellar radii, and takes into account radiative cooling and thermal conduction. We do not adopt ad hoc heating function; heating is automatically calculated from the solutions of Riemann problem at the cell boundaries. In the solar wind case we impose transverse photospheric motions with velocity ~1 km/s and period between 20 seconds and 30 minutes, which generate outgoing Alfvén waves. We have found that the dissipation of Alfvén waves through compressive wave generation by decay instability is quite effective owing to the density stratification, which leads to the sufficient heating and acceleration of the coronal plasma. Next, we study the evolution of stellar winds from main sequence to red giant phases. When the stellar radius becomes ~10 times of the Sun, the steady hot corona with temperature 106 K, suddenly disappears. Instead, many hot and warm (105 – 106 K) bubbles are formed in cool (T < 2 × 104 K) chromospheric winds because of the thermal instability of the radiative cooling function; the red giant wind is not a steady stream but structured outflow.

The numerical method developed by Veselovsky & Ivanov (2006), together with magnetograms of the Sun obtained at the photospheric level were used to calculate the coronal magnetic field with open, closed and intermittent topology during March-December 2007. The results of the modelling are compared with stereoscopic images and movies of the corona observed by EUV telescopes onboard STEREO and SOHO spacecraft. The sources of the permanent and transient high speed solar wind streams as well as the sector structure and the heliospheric plasma sheet observed at the Earth's orbit by the ACE and STEREO spacecraft are discussed.