In the impulsive phase of solar flares, the electrostatic waves can be excited during magnetic reconnection. The proton and electron at reconnecting X points can be accelerated by perpendicular propagating electrostatic waves.

The spectral and source characteristics of a complex radio burst observed with the spectrometers of China and the Nobeyama Radio Heliograph are analyzed. This burst presents two separate burst peaks occurred in different frequency range (broad-band microwave and narrow-band decimeter wavelengths). We stress that the late phase radio bursts in decimeter wavelength corresponding to the post-flare loops may be the radio homologous flare.

We report the temporal evolution of the long lasting solar flare observed on June 6, 2000 (15:00 – 17:00 UT) by the Brazilian Solar Spectroscope (BSS) at INPE. We emphasize the identification of the decimetric fine structures, such as “fiber” and “zebra” emissions, including the unique case of harmonic “zebra” emissions in the decimetric band reported, radio pulsations, type III bursts and variants, recorded during this event in the frequency range of (1.2 – 1.7 GHz). The main characteristics of fine structures recorded are presented.

The solar magnetic cycle affects all levels of the Sun including the convection zone, photosphere, chromosphere and corona. Recent advances in solar space missions (Yohkoh, SOHO and others) and, also, ground-based observations provide us an excellent opportunity to investigate solar magnetic activity in detail, and to draw a new picture of the solar magnetic cycle. Magnetic field appears on the solar surface as a result dynamo processes in the convection zone, and forms bipolar complexes of solar activity. These complexes can be seen in the photosphere as dark sunspots surrounded by the bright plages extended into chromosphere, with arcades of coronal loops best observed in EUV and soft X-rays. The coronal loops reflect the large-scale magnetic structure of complexes of activity. The new data reveal fundamental changes in the magnetic topology during the solar cycle, and details of the polar magnetic field reversals occurring near the sunspot maximum. The solar synoptic maps obtained from the photospheric and coronal data display a close correlation between the erupted magnetic flux and coronal emissions and show large-scale magnetic connectivities. The brief review of solar cycle studies is presented.

An overview is presented of large-scale coronal structures as observed in soft X-rays (SXR) and extreme ultraviolet (EUV) wavelengths in the context of their magnetic properties. These structures include large-scale interconnecting and trans-equatorial loops, coronal streamers, coronal holes, filaments and filament channels. Since the general appearance of the corona and its structures change with evolving underlying fields, evolutionary trends and solar cycle dependence of these coronal structures are discussed as well.

Evidence of coronal oscillations over the interior of supergranular cells was found through SUMER observations. The observations are rasters of quiet Sun regions and the oscillations were detected, in the Ne ${\sc viii}\, 770 \AA$ Doppler maps, as a characteristic pattern. It should be noted that the Ne ${\sc viii}\,$ ion has coronal formation temperature (650 000 K) and that reports of oscillations in the quiet Sun corona are scarce. Magnetic extrapolation from MDI magnetogram showed that at the location where the oscillation was detected, the gas and magnetic pressures get equalized ($\beta$=1) higher in the atmosphere, compared to the surrounding, non oscillating quiet Sun. This could indicate a non-compressible wave propagating inside the gas dominated medium of the cell causing the detected oscillation.

Transport of the solar background large-scale magnetic regions is followed between individual consecutive magnetic synoptic charts derived from observing data of Kitt Peak NSO. During many solar rotations the horizontal magnetic flux displacement was described by large-scale horizontal transport velocities, inferred in many points over the whole solar photosphere. Large-scale transport velocities contains from both axially symmetric and non-axially symmetric components. The first one describes zonal and meridional global transport studied in time interval during three last solar activity cycles. Cycle dependent global velocities are found as values varying in heliographic latitude and in the phase of the solar cycle.

We discuss a large flare that was observed simultaneously by RHESSI in hard X–rays and by the Nobeyama Radio Heliograph (NoRH) in microwaves. The imaging observations made both by RHESSI and NoRH show many interesting features which may be relevant for producing realistic flare models.

We analyze three solar active regions observed with the MDI instrument onboard SoHO (Scherrer et al. 1995). We apply the time-distance helioseismology formalism to derive the travel times of acoustic waves propagating through these active regions. The inversion of these acoustic travel times gives us access to the 3D sound-speed structure below the sunspots. We compare the main characteristics of these inversion results as a function of the active region size and magnetic field strength.

Ulysses spacecraft discovered the long-period, outwardly propagating Alfvén waves in the solar polar regions (Balogh et al. 1995). Here we suggest that the waves may be generated in the solar interior due to the pulsation of the Sun in the fundamental radial mode or in low-frequency g-modes. The period of fundamental mode is about 1 hour, while the period of g-modes can be longer. The pulsation causes a periodical variation of density and large-scale magnetic field, this affecting the Alfvén speed in the solar interior. Consequently the Alfvén waves with the half frequency of pulsation (i.e. with the double period) can be parametrically amplified in the interior below the convection zone due to the recently suggested swing wave-wave interaction. Therefore the amplified Alfvén waves have periods of several hours. The waves can propagate upwards through the convection zone to the solar atmosphere and cause the observed long-period Alfvén oscillations in the solar wind.

Recently, high resolution observations by SOHO and TRACE spacecraft have identified oscillating loops and propagating waves in the solar coronal. These new discoveries established a new discipline that is known as coronal seismology. The importance of this lies in the potential for the diagnostics of coronal structures and knowledge of coronal heating. We present a study of the effects of radiative cooling and heating processes on longitudinal waves in coronal loops. We find that radiation and heating results in a clear modification in the evolution of temperature and pressure perturbations but in slight effect on the decay time of the wave.

Based on photospheric vector magnetograms obtained at Huairou Observing Station and BBSO, we studied the evolution of magnetic nonpotentiality and energy transport in NOAA AR 10720. Daily changes of vector magnetic field was analyzed. Shear angle, helicity and free energy density which were deduced from the data were examined.

A New EFR on January 13 brought in magnetic nonpotentiality strong shear angle, free energy and complexity(multiple neutral line and opposite sign helicity) which touched off AR activity, support the idea that upper atmospheres critical state may be made by continues changes on the photosphere.

Observations of source regions of coronal mass ejections have progressed enormously in the past decade with the observations from SOHO and Yohkoh. Progress has been made on understanding magnetic helicity, coronal dimming, coronal waves and flares in terms of their relationship to CMEs. Observations have been used to verify and disagree with models such as tether-cutting, kink instabilities and the breakout model. We will describe the observations, recent models, and how future observations from the Solar-B and STEREO missions will address many unanswered questions.

The exact solution of the evolution equation for the magnetic field in ideal MHD, Callebaut (2006), with an azimuthal velocity which is function of $r$ and $\vartheta$ only (spherical coordinates) is applied to a bipolar magnetic seed field and to a quadripolar field. Resistivity and $\alpha$-effect are not yet taken into account, but the extensions are possible. From the surface observations we had derived an approximate analytic expression for the differential rotation in order to work fully analytically in the application. Qualitatively the results for a quadripolar field are as for a bipolar seed field. The main features are the same: for some latitudes the field may increase by two orders of magnitude, the separation between sunspots and polar faculae is clearcut, there is, relatively speaking, a too strong amplification in the polar regions (the latter occurs in other models too). The hypothesis that the seed fields are situated at the tachocline is not required: the amplification is active throughout the whole convective zone, albeit with different strengths, and thus during the transit of the flux tubes from tachocline to the solar surface too.

The non-thermal electrons accelerated during solar flares can produce enhanced and broadened chromospheric lines when they precipitate into the chromosphere. In this paper, we propose a method to diagnose the non-thermal processes using two chromospheric lines, ${H\alpha}$ and Ca ${\sc ii} 8542 \AA}$ lines. First, we perform non-LTE calculations of these two lines for various (thermal) model atmospheres and (non-thermal) electron beams. Since the two lines have different sensitivities to the non-thermal electrons, a set of line spectra can uniquely determine a model atmosphere and an electron beam. We then apply this method to a solar flare for which we have observed two-dimensional spectra of the two lines. In particular, we examine the temporal variation of thermal vs. non-thermal effects in flare bright kernels, as well as the spatial variation across flare ribbons. The results show clearly that the non-thermal effects appear most obviously at the flare maximum, and preferentially at the outer edges of flare ribbons. The results are consistent with flare theoretical models.

Magnetohydrodynamic equilibria for a plasma in a gravitational field are investigated analytically. For equilibria with one ignorable spatial coordinate, the equations reduce to a single nonlinear elliptic partial differential equation for the magnetic potential A, known as the Grad-Shafranov equation. Specifying the arbitrary functions in the latter equation, one gets a nonlinear elliptic partial differential equation (the sinh Poisson equation). Analytical solutions of this equation are obtained for the case of an isothermal atmosphere in a uniform gravitational field. The solutions are obtained by using the tanh method, and are adequate for describing parallel filaments of diffuse, magnetized plasma suspended horizontally in equilibrium in a uniform gravitational field.

The solar prolateness (also known as Ovalisation, a french origin name) of the extended dynamical chromosphere is established from measurements performed above 2 Mm heights during the years of solar minimum, using the H$\alpha$, Ca II K and HeII 304 line emissions from both ground-based and space-based observations. Coronal X-EUV emissions usually penetrate deep enough into the chromosphere to completely mask this effect on transition region lines and produce the so-called coronal hole effect. However, cool lines like H$\alpha$ and Ca II lines, do NOT show this Coronal Hole (CH) effect. Coronal lines and HeI (D3; 1083 nm) do show CHs but do not show the prolateness effect. We first briefly review different methods which can potentially be used to measure the prolateness. Further we note the similarity of the geometric behaviour of the prolateness and its variation along the solar cycle compared to the behaviour of the fast solar wind. It suggests the same origin possibly related to the emergence of the small scale network and internetwork magnetic field towards the corona and small scale magnetic reconnections. A simple geometric model was proposed to explain the effect of the prolateness of the solar chromosphere by considering that the specific dynamical part of the solar atmosphere above the 2 Mm level, being a mixture of up and down moving jets of chromospheric matter with the coronal plasma between them, is responsible for the solar prolateness (Filippov and Koutchmy, 2000). We however note that polar regions are also showing different types of activity in the low corona, including small prominence eruptions seen e.g. in H$\alpha$ and linear jets seen in SXR and EUV as well as in W-L (eclipses). Some kind of dynamical dissipation of the newly emerged magnetic field is needed. More systematic measurements should be done to build a more complete, possibly 3D, picture to explain the extended in the horizontal direction lifting effect of a large part of the polar chromosphere.

SOLARNET is a medium size high resolution solar physics mission proposed to CNES and ESA for a new start in 2007 and a possible launch in 2012 (CNES) or later (ESA Cosmic Vision framework: 2015–2016). Partnerships with India and China are under discussion, and several European contributions are considered. At the center of the SOLARNET mission is a 3-telescope interferometer of 1 meter baseline capable to provide 40 times the best ever spatial resolution achieved in Space with previous, current or even planned solar missions: 20 mas - 20 km on the Sun in the FUV. The interferometer is associated to an on-axis Subtractive Double Monochromator coupled to an Imaging Fourier Transform Spectrometer capable of high spectral (0.01 nm) and high temporal resolutions (50 ms) on a field of view of 40 arcsec and covering the FUV and UV spectral domains (from 117.5 to 400 nm). This will allow to access process scales of magnetic reconnection, dissipation, emerging flux and much more, from the chromosphere to the low corona with emphasis on the transition zone where the magnetic confinement is expected to be maximum. A whole new chapter of the physics of solar magnetic field structuring, evolution and mapping from the photosphere to the high atmosphere will be opened. The interferometer is completed by instruments providing larger field of view and higher temperature (EUV-XUV coronal imaging & spectroscopy) to define the context and extension of the solar phenomena. The 3-telescope interferometer design results of an extensive laboratory demonstration program of interferometric imaging of extended objects. We will review the scientific program of SOLARNET, describe the interferometer concept and design, present the results of the breadboard and give a short overview of the mission aspects. In a different category, LAIME, the Lyman Alpha Imaging-Monitor Experiment, is a remarkably simple (no mechanisms) and compact full Sun imager to be flown with TESIS on the CORONAS-PHOTON mission in 2008. It could be the only chromospheric imager to be flown in the next years, supporting Solar-B, STEREO, SDO and the Belgian LYRA Lyman Alpha flux monitor. We will give a short description of this unique 60 mm aperture imaging telescope, dedicated to the investigation of the UV sources of solar variability and of the chromospheric and coronal disruptive events (Moreton waves, prominences, CMEs, etc.).

The problems of required conditions and possible consequences of the super - compression (up to $R_m\sim 3R_E$) of the Earth's magnetosphere by giant CME are investigated by the methods of laboratory and computer simulations. A useful relation between an expected magnetopause location $R_m^*$ and the kinetic plasma energy $E_0$ of spherical plasma cloud (exploded at distance $R_0$) was obtained $R_m^*/R_0\approx 0,75/{\ae}^{1/6}$ and tested by MHD – model of Nikitin & Ponomarenko (1994) with the using their main energetic criterion of the problem ${\ae}=3E_0 R_0^3/\mu^2$ (for magnetic moment $\mu$ of point obstacle in vacuum). This relation could describe rather well an observed compression ($R_m\sim 5-6 R_E$ for CME with energy $10^{32}\, ergs$ and effective value $E_0\sim 10^{33} ergs,$ into $4\pi$) and predicts $R_m^*\leq 3R_E$ in a probable case of Mega Flare with the total energy release $\sim 10^{34}\, ergs$ and possible $E_0\sim 5\cdot 10^{34}\, ergs$ according to Kane et al. (1995) and Tsurutani et al. (2003). Some most important features of the formation such Artificial Magnetosphere (AM) structure and its possible influence onto various geospheres media (or technosphere areas) could be successfully studied in the simulative experiments at KI-1 facility of ILP with Laser Plasmas (LP) of $E_0$ up to $kJ$ and dipole $\mu\sim 10^7\, G\cdot cm^3$ as was shown by Ponomarenko et al. (2001) and Zakharov (2003). But the main problem of such planned AMEX experiment (at ${\ae}\sim 50$ for $R_0=75\, cm$) is the influence of finite value of ion magnetization $\varepsilon_m=R_L/R_m^*$ based on the ion Larmor radius $R_L=mcV_0/ezB_d,$ where $V_0\sim 100\, km/s$ is the expansion velocity of LP and $B_d$ is the initial dipole field at the point $R_m^*.$ Of coarse, $\varepsilon_m\ll 1$ in a real space conditions (excluding cases of Mercury or asteroids, explored by Omidi et al. (2004)) while in the laboratory to fulfill both need constrains ${\ae}\gg 1$ and $\varepsilon_m\ll 1$ we should use a thermonuclear plasma and devices. To overcome this problem we did a 3D/PIC – calculations by hybrid model of Kyushu University, described by Muranaka et al. (2001), to find out a critical value of $\varepsilon_m^*$ $(\approx 0,2-\!0,3),$ which need for MHD – like interaction of exploding plasmas with magnetic dipole.

The paper reports about several actual problems of the solar wind and solar energetic particle studies. Primary focus is on unsolved questions. The clear and sharp boundary in the phase space between solar wind plasma particle populations and “solar energetic particles” does not exist. Because of this separate consideration of “solar energetic particles” has only limited applicability and needs some reservations, which should be clearly stated and not forgotten to avoid possible errors and misinterpretations, which sometimes happen in the literature. In any case, the solar wind particles often serve as a big reservoir for acceleration (or cooling) of less abundant energetic particles. Solar wind and solar energetic particles are just two selected populations (big and small) in their joint distribution functions. It is very difficult and even impossible in many instances to have demarcation between particle populations in the energy space or indicate their ultimate “origins” in the coordinate space. It is because of the absence of localized “accelerators”, “heaters” or “sources” of particles. All these three categories mentioned above often have very limited physical meaning, but sometimes they can be useful and localized in the momentum and coordinate space. We are still too far from complete knowledge and understanding of many relevant questions in this regard.