Narrow Results

Ulysses is the first spacecraft ever to fly over the poles of the sun. Its primary goal is to explore the heliosphere in four dimensions: three spatial dimensions, and time. An overview of some of the recent results from the mission will be presented. Particular emphasis will be given to the changes occurring in the 3-dimensional heliosphere from solar minimum to solar maximum, and their effects on energetic particles and cosmic rays.

The changes of the structure in the energy range of the interplanetary magnetic field (IMF) turbulence versus solar activity can be considered as one of the important reasons of the long period (11-year) modulation of galactic cosmic ray (GCR) intensity; the amplitude of the 27-day variation of GCR anisotropy is greater in the qA > 0 periods than in the qA < 0 periods of the solar magnetic cycles in a good correlation with the similar changes of the 27-day variation of GCR intensity.

The Japanese/US/UK space mission, Hinode, was launched successfully in September 2006. Now, more than a year after the commissioning of the spacecraft and instruments, Hinode is unveiling a new view of the Sun. Hinode's goal is to help us to understand solar activity, and to link activity on (and below) the surface to the outer corona. This review will describe how the initial results are overturning our understanding of the Sun and will look to the future to anticipate what further discoveries might be made. In particular I will describe the areas of basic magnetohydrodynamic (MHD) processes such as magnetic reconnection and Alfvén waves, the formation of both the fast and slow solar winds and the triggering of flares and coronal mass ejections.

The interaction of the solar wind with the surrounding interstellar medium (ISM) forms a cavity in the ISM. This cavity is called the heliosphere (influence sphere) of the Sun. Numerical models were developed using hydrodynamic (HD) and magneto-hydrodynamic (MHD) equations to simulate the interaction of the different fluids in the heliosphere. These models showed that the heliosphere is driven by the interaction of the ionized solar wind, which expands away from the Sun at supersonic speeds, and the local interstellar medium (LISM). Also of importance is the effect of neutral particles in the LISM and magnetic fields. These descriptions then provide the background environment in which c011mic ray transport and acceleration can be calculated as they are transported from the heliospheric boundary up to Earth.

The Suzaku satellite observed a region close to the supernova remnant SN1006 twice on September 12, 2005, and on January 26, 2006. During the first observation the region was bright in a soft X-ray band. Comparing the CCD spectra of the two observations, we found that the soft X-ray brightening can be explained by emission lines from ionized carbon, nitrogen, oxygen, iron, and so on. Emission lines due to the transitions from the M shell or higher to the K shell were included. These characteristics strongly suggest that the origin of the soft X-ray brightening is the charge exchange between solar wind ions and neutral atoms in the Earth atmosphere.

The possibility of the clouds of Venus providing habitats for extremophilic microorganisms has been discussed for several decades. We show here that the action of the solar wind leads to erosion of parts of the atmosphere laden with aerosols and putative microorganisms, forming a comet-like tail in the antisolar direction. During inferior conjunctions that coincide with transits of the planet Venus this comet-like tail intersects the Earth's magnetopause and injects aerosol particles. Data from ESA's Venus Express spacecraft and from SOHO are used to discuss the ingress of bacteria from Venus into the Earth's atmosphere, which we estimate as ~10¹¹–10¹³ cells for each transit event.