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This book is devoted to eruptive phenomena on the Sun, the most dangerous sources of space weather disturbances. It discusses the latest achievements in this field, described in the scientific literature and obtained by the author himself. The initial chapters of the book give a brief description of the role of the Sun in the life and history of mankind, a general description of the solar interior and the atmosphere of the Sun, the causes and drivers of solar activity and its impact on the Earth's environment and human life. The book provides a detailed description of eruptive phenomena on the Sun, a review of observations of solar activity and theoretical ideas about the mechanisms and causes of a sudden release of energy in the solar atmosphere. Much attention is paid to the solar magnetic fields, their characteristic features and measured values in the photosphere, the observed manifestations in the chromosphere and corona, and methods for extrapolating photospheric data to the upper layers of the solar atmosphere. It is assumed that the magnetic field is the source of energy suddenly released during eruptive phenomena observed in the form of flares, prominence eruptions and coronal mass ejections (CMEs). Energy is accumulated and stored in the non-potential (associated with electric currents) part of the coronal magnetic field (free magnetic energy). This part of the field is the most variable and can provide energy for fast eruptive processes. CMEs, propagating through the interplanetary medium, significantly perturb it and cause the strongest geomagnetic storms when they affect the Earth's magnetosphere. The prediction of the arrival of the CME is the key problem of the entire space weather forecast. Thus, pre-eruptive conditions in CME source regions are of great importance. Solar prominences and filaments are considered the most likely progenitors of CMEs. Most of the book is devoted to the description and analysis of their equilibrium and stability. It is shown that there are measurable characteristics of the proximity of the prominence to the instability threshold, which can be very useful in the problem of space weather forecasting. The book contains many illustrations and links to the latest scientific articles and reviews on the topic. It will be useful to researchers in the field of astrophysics, solar physics, geophysics, as well as PhD and graduate students.

Solar activity. --- Sun. --- Astrophysics. --- Astronomy --- Plasma astrophysics. --- Solar Physics. --- Astronomy, Observations and Techniques. --- Astrophysical Plasma. --- Observations.

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This book clears up some confusion in the field of star formation and proposes a solution to a problem that remains unsolved for more than a decade. Observations of molecular clouds show that dense filaments are the sites of present-day star formation, and it is thus necessary to understand the filament formation process because the filament is an initial condition in a star formation process. Theoretical studies suggest that shock waves in molecular clouds trigger filament formation. Several different mechanisms have been proposed, and the formation mechanism of the observed star-forming filaments is expected to be clarified. In this book, the author performs a series of isothermal magnetohydrodynamics (MHD) simulations of filament formation and identifies the formation mechanisms. It is found that the dominant filament formation mode changes with the velocity of the shock waves that trigger the filament formation. The filament width plays an important role in determining the fragmentation scale by self-gravity, and observations show that the width 0.1 pc is universal. On the other hand, in theory the width of the supercritical filaments was considered to be narrowed by self-gravity. Recent studies suggest that massive filaments are bound by the slow shocks that are caused by accretion flows onto the filaments. Since the wavefront of such a slow shock is known to be unstable as a slow shock instability (SSI), the accretion ram pressure is expected to be converted into thermal/turbulent pressure across the shock front, which potentially maintains the width. In the scale of dense filaments, ambipolar diffusion (AD) suppresses the SSI at small scales. The influence of AD on SSI is investigated using two-dimensional MHD simulations, and the nonlinear evolution of the SSI with AD is found to drive turbulences. The book demonstrate the effect of SSI including AD onto the filament evolution.

Astrophysics. --- Plasma astrophysics. --- Plasma waves. --- Plasma turbulence. --- Astrophysical Plasma. --- Waves, instabilities and nonlinear plasma dynamics. --- Turbulence in plasmas. --- Stars --- Formation.

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This thesis addresses the feasibility of the production of ultra-high-energy cosmic rays in starburst galaxies and active galactic nuclei. These astrophysical objects were theoretically proposed as candidate sources a long time ago. Nevertheless, the interest in them has been recently renewed due to the observational data collected by the Pierre Auger Observatory and the Telescope Array. In this work, a comprehensive review of the current status of the research on cosmic rays accelerators is provided, along with a summary of the principal concepts needed to connect these relativistic particles with electromagnetic and neutrino observations in the multi-messenger era. On one hand, the hypothesis of accelerating particles with energies above 10¹⁸ eV in starburst superwinds is carefully revisited, taking into account the constraints imposed by the most recent electromagnetic observations. On the other hand, an alternative new model for the gamma emission of the nearby active galaxy NGC 1068 is presented. The implications of the results of these studies are discussed in terms of the contemporary observatories and prospects for future experiments are offered.

Space research --- Astrophysics --- Astronomy --- Experimental nuclear and elementary particle physics --- Nuclear physics --- astrofysica --- ruimte (astronomie) --- astronomie --- atoomfysica --- Astrophysics. --- Plasma astrophysics. --- Particles (Nuclear physics). --- Astronomy, Observations and Techniques. --- Astrophysical Plasma. --- Particle Physics. --- Observations.

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This open access book serves as a concise primer introducing the non-specialist reader to the physics of solar energetic particles (SEP). It systematically reviews the evidence for the two main mechanisms which lead to the so-called impulsive and gradual SEP events. This second edition contains two completely new chapters discussing element abundances and shock waves, reflecting new theoretical, modeling, and observational results. Existing chapters have been substantially expanded or updated with additions placed in a broader context. More specifically, the author discusses the timing of the onsets of SEPs, their longitude distributions, their high-energy spectral shapes, their correlations with other solar phenomena, as well as the all-important elemental and isotopic abundances. The book relates impulsive SEP events to magnetic reconnection in solar flares and jets. The concept of shock acceleration by scattering on self-amplified Alfvén waves is introduced, as is the evidence of reacceleration of impulsive-SEP material in the seed population accessed by the shocks in gradual events. The text then develops processes of transport of ions out to an observer. Finally, a technique to determine the source plasma temperature in both impulsive and gradual events is demonstrated.The author also mentions the role of SEP events as a radiation hazard in space and briefly discusses the nature of the main particle telescope designs that have contributed to most of the SEP measurements.

Astronomy. --- Astrophysics. --- Plasma (Ionized gases). --- Space sciences. --- Atmospheric sciences. --- Astronomy, Astrophysics and Cosmology. --- Plasma Physics. --- Space Sciences (including Extraterrestrial Physics, Space Exploration and Astronautics). --- Atmospheric Sciences. --- Atmospheric sciences --- Earth sciences --- Atmosphere --- Science and space --- Space research --- Cosmology --- Science --- Astronomy --- Gaseous discharge --- Gaseous plasma --- Magnetoplasma --- Ionized gases --- Astronomical physics --- Cosmic physics --- Physics --- Astronomy, Astrophysics and Cosmology --- Plasma Physics --- Space Sciences (including Extraterrestrial Physics, Space Exploration and Astronautics) --- Atmospheric Sciences --- Solar Physics --- Astrophysical Plasma --- Waves, instabilities and nonlinear plasma dynamics --- Space Physics --- Atmospheric Science --- Open Access --- Impulsive SEP events --- Gradual SEP events --- Space Weather --- Coronal elemental abundances --- Solar wind --- Space plasma physics --- SEP measurements --- Coronal mass ejections --- Theoretical & mathematical astronomy --- Astronautics

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The essential introduction to magnetic reconnection—written by a leading pioneer of the fieldPlasmas comprise more than 99 percent of the visible universe; and, wherever plasmas are, magnetic reconnection occurs. In this common and yet incompletely understood physical process, oppositely directed magnetic fields in a plasma meet, break, and then reconnect, converting the huge amounts of energy stored in magnetic fields into kinetic and thermal energy. In Magnetic Reconnection, Masaaki Yamada offers an illuminating synthesis of modern research and advances on this important topic. Magnetic reconnection produces such phenomena as solar flares and the northern lights, and occurs in nuclear fusion devices. A better understanding of this crucial cosmic activity is essential to comprehending the universe and varied technological applications, such as satellite communications. Most of our knowledge of magnetic reconnection comes from theoretical and computational models and laboratory experiments, but space missions launched in recent years have added up-close observation and measurements to researchers’ tools. Describing the fundamental physics of magnetic reconnection, Yamada connects the theory with the latest results from laboratory experiments and space-based observations, including the Magnetic Reconnection Experiment (MRX) and the Magnetospheric Multiscale (MMS) Mission. He concludes by considering outstanding problems and laying out a road map for future research.Aimed at advanced graduate students and researchers in plasma astrophysics, solar physics, and space physics, Magnetic Reconnection provides cutting-edge information vital area of scientific investigation.

Magnetic reconnection. --- SCIENCE / Physics / Magnetism. --- Acceleration. --- Accretion disk. --- Ampere. --- Annihilation. --- Astrophysical plasma. --- Astrophysics. --- Bremsstrahlung. --- Collision frequency. --- Collisionality. --- Coronal loop. --- Coronal mass ejection. --- Coulomb collision. --- Current density. --- Current sheet. --- Cyclotron. --- Debye length. --- Diffusion layer. --- Dissipation. --- Drift velocity. --- Dynamo theory. --- Electric field. --- Electrical resistivity and conductivity. --- Electron temperature. --- Electrostatics. --- Energy transformation. --- Experimental physics. --- Fermi acceleration. --- Feynman diagram. --- Field effect (semiconductor). --- Field line. --- Fine structure. --- Flux tube. --- Fusion power. --- Gauge theory. --- Gyroradius. --- Hall effect. --- Inductance. --- Induction equation. --- Instability. --- Interferometry. --- Ion acoustic wave. --- Ionization. --- Kinetic theory of gases. --- Kink instability. --- Landau damping. --- Langmuir probe. --- Length scale. --- Lorentz force. --- Madison Symmetric Torus. --- Magnetar. --- Magnetic confinement fusion. --- Magnetic diffusivity. --- Magnetic dipole. --- Magnetic energy. --- Magnetic field. --- Magnetic flux. --- Magnetic helicity. --- Magnetization. --- Magnetohydrodynamics. --- Magnetopause. --- Magnetosheath. --- Magnetosonic wave. --- Magnetosphere. --- Maxwell–Boltzmann distribution. --- Mean free path. --- Momentum transfer. --- Neutral beam injection. --- Nonlinear optics. --- Nuclear fusion. --- Paramagnetism. --- Particle physics. --- Pitch angle (particle motion). --- Plasma (physics). --- Plasma acceleration. --- Plasma oscillation. --- Plasma parameter. --- Plasma parameters. --- Plasma stability. --- Plasmoid. --- Quadrupole. --- Relativistic plasma. --- Reversed field pinch. --- Safety factor (plasma physics). --- Scattering. --- Skin effect. --- Solar flare. --- Spacecraft. --- Spatial scale. --- Spheromak. --- Stark effect. --- Substorm. --- Synchrotron radiation. --- Thermodynamic equilibrium. --- Thomson scattering. --- Tokamak. --- Two-dimensional space. --- Van Allen radiation belt. --- Weibel instability. --- X-ray. --- Annihilation, Magnetic field --- Magnetic field annihilation --- Magnetic field line merging --- Merging, Magnetic field line --- Reconnection, Magnetic --- Reconnection (Astronomy) --- Astrophysics --- Geophysics --- Magnetic fields