The third COSPAR Colloquium entitled Solar Wind Seven was held in Goslar, Germany in September 1991. Twenty-two countries were represented by scientists, many of whom are leading experts in the area of heliospheric physics. The Proceedings reflect current research on solar wind and particularly emphasizes the source regions. The main topics covered encompass Coronal Heating and Solar Wind Acceleration; Large-Scale Structure of the Interplanetary Medium; Minor Ions, Neutrals and Cosmic Rays in the Heliosphere; Kinetic Physics, Waves and Turbulence and finally Heliospheric Dynamic Phenomena.
This book provides an overview of solar wind turbulence from both the theoretical and observational perspective. It argues that the interplanetary medium offers the best opportunity to directly study turbulent fluctuations in collisionless plasmas. In fact, during expansion, the solar wind evolves towards a state characterized by large-amplitude fluctuations in all observed parameters, which resembles, at least at large scales, the well-known hydrodynamic turbulence. This text starts with historical references to past observations and experiments on turbulent flows. It then introduces the Navier-Stokes equations for a magnetized plasma whose low-frequency turbulence evolution is described within the framework of the MHD approximation. It also considers the scaling of plasma and magnetic field fluctuations and the study of nonlinear energy cascades within the same framework. It reports observations of turbulence in the ecliptic and at high latitude, treating Alfvénic and compressive fluctuations separately in order to explain the transport of mass, momentum and energy during the expansion. Further, existing models are compared with direct observations in the heliosphere. The problem of self-similar and anomalous fluctuations in the solar wind is then addressed using tools provided by dynamical system theory and discussed on the basis of available models and observations. The book highlights observations of Yaglom’s law in solar wind turbulence, which is one of the most important findings in fully developed turbulence and directly related to the long-lasting and still unsolved problem of solar wind plasma heating. Lastly, it includes a short chapter dedicated to the kinetic range of fluctuations, which has recently been receiving more attention from the space plasma community, since this is inherently related to turbulent energy dissipation and consequent plasma heating. It particularly focuses on the nature and role of the fluctuations populating this frequency range, and discusses several model predictions and recent observational findings in this context.
The First Edition of The Sun from Space, completed in 1999, focused on the early accomplishments of three solar spacecraft, SOHO, Ulysses, and Yohkoh, primarily during a minimum in the Sun’s 11-year cycle of magnetic activity. The comp- hensive Second Edition includes the main ndings of these three spacecraft over an entire activity cycle, including two minima and a maximum, and discusses the signi cant results of six more solar missions. Four of these, the Hinode, RHESSI, STEREO, and TRACE missions were launched after the First Edition was either nished or nearly so, and the other two, the ACE and Wind spacecraft, extend our investigations from the Sun to its varying input to the Earth. The Second Edition does not contain simple updates or cosmetic patch ups to the material in the First Edition. It instead contains the relevant discoveries of the past decade, integrated into chapters completely rewritten for the purpose. This provides a fresh perspective to the major topics of solar enquiry, written in an enjoyable, easily understood text accessible to all readers, from the interested layperson to the student or professional.
The workshop "Nonhnear MHD Waves and Turbulence" was held at the - servatoire de Nice, December 1-4, 1998 and brought together an international group of experts in plasma physics, fluid dynamics and applied mathematics. The aim of the meeting was to survey the current knowledge on two main topics: (i) propagation of plasma waves (like Alfven, whistler or ion-acoustic waves), their instabilities and the development of a nonlinear dynamics lea ding to solitonic structures, wave collapse or weak turbulence; (ii) turbulence in magnetohydrodynamic flows and its reduced description in the presence of a strong ambient magnetic fleld. As is well known, both aspects play an important role in various geophysical or astrophysical media such as the - gnetospheres of planets, the heliosphere, the solar wind, the solar corona, the interplanetary and interstellar media, etc. This volume, which includes expanded versions of oral contributions pre sented at this meeting, should be of interest for a large community of resear chers in space plasmas and nonlinear sciences. Special effort was made to put the new results into perspective and to provide a detailed literature review. A main motivation was the attempt to relate more closely the theoretical un derstanding of MHD waves and turbulence (both weak and strong) with the most recent observations in space plasmas. Some papers also bring interesting new insights into the evolution of hydrodynamic or magnetohydrodynamic structures, based on systematic asymptotic methods.
Until the advent of space physics, astrophysical plasmas could be studied only using ground-based observations. Although observational methods have advanced over recent decades, the merging of heliospheric physics with astrophysics is far from complete due to the vastly different techniques employed by astronomers and space physicists. That astrophysical plasmas can be studies directly is a major advance in astrophysical research. The solar wind from the Sun is only one of many examples of solar winds, but it provides scientists with a basis for understanding how these formerly disparate disciplines are related. Cosmic Winds and the Heliosphere is a comprehensive sourcebook on conceptually correlated topics in astrophysical winds and heliospheric physics. The contributors review the various kinds of winds, such as solar wind, winds of cataclysmic variables, and winds from pulsating stars. They then examine the physics of wind origin and physical phenomena in winds. including heliospheric shocks, magnetohydrodynamic turbulence, and kinetic phenomena. A final section considers interactions with surrounding media, with contributions ranging from studies of the interstellar cloud surrounding the solar system to considerations of solar wind interaction with comets. Prepared to the scrupulous standards of the University of Arizona Space Science Series, Cosmic Winds and the Heliosphere is an essential volume for astronomers and space physicists.
Spacecraft such as the Pioneer, Vela, and Voyager have explored the interplanetary medium between the orbits of Mercury and Pluto. The insights derived from these missions have been successfully applied to magnetospheric, astro-solar, and cosmic ray physics. This book is an overview of these insights, using magnetohydrodynamic (MHD) flows as the framework for interpreting objects and processes observed in the interplanetary medium. Topics include various types of MHD shocks and interactions among them, tangential and rotational discontinuities, force-free field configurations, the formation of merged interaction regions associated with various types of flows, the destruction of flows, the growth of the Kelvin-Helmholtz instability and formation of a heliospheric vortex street, the development of multifractal fluctuations on various scales, and the evolution of multifractal intermittent turbulence. Students and researchers in astrophysics will value the data from these missions, which provide confirmation of many theoretical models of the interstellar medium.
It is well known that stellar winds are variable, and the fluctuations are often cyclical in nature. This property seems to be shared by the winds of cool and hot stars, even though their outflows are driven by fundamentally different physical mechanisms. Since very similar models have been proposed to explain the cyclical wind variations observed in a wide variety of stars, the time was ripe for astrophysicists from many different sub-disciplines to present the state of the art in a concise form. The proceedings will provide a useful, up-to-date overview of the observations, interpretation, and modelling of the time-dependent mass outflows from all sorts of stars.
Physics of the Inner Heliosphere gives for the first time a comprehensive and complete summary of our knowledge of the inner solar system. Using data collected over more than 11 years by the HELIOS twin solar probes, one of the most successful ventures in unmanned space exploration, the authors have compiled six extensive reviews of the physical processes of the inner heliosphere and their relation to the solar atmosphere. Researchers and advanced students in space and plasma physics, astronomy, and solar physics will be surprised to see just how closely the heliosphere is tied to, and how sensitively it depends on, the sun. Volume 2 deals with particles, waves, and turbulence, with chapters on: - magnetic clouds - interplanetary clouds - the solar wind plasma and MHD turbulence - waves and instabilities - energetic particles in the inner solar system
The launch in October 1990 of the joint ESA-NASA Ulysses mission marked the start of a new era in the study of the heliosphere. For the fIrst time, in-situ observations are being made covering the full range of heliographic latitudes. Following the successful gravity-assist manoeuvre at Jupiter in February 1992, Ulysses left the ecliptic plane in a southerly direction and headed back toward the Sun, passing over the southern solar pole in mid-1994. To mark these unique events, the 28th ESLAB Symposium, held in Friedrichs hafen, Germany, on 19-21 April 1994, was devoted to "The High Latitude Helio sphere". Following on from the highly successful 19th ESLAB Symposium "The Sun and the Heliosphere in Three Dimensions" (Les Diablerets, 1985), the purpose of the meeting was to review out-of-ecliptic results from the Ulysses mission obtained to date, and to provide a focus for the fIrst polar pass. Relevant results from other space missions, as well as ground-based and theoretical studies, were also included. Attended by 130 scientists, the main themes of the Symposium were The Sun and Corona, Large-Scale Heliospheric Structure, Energetic Particles in the Heliosphere, Cosmic Rays in the Heliosphere, and Interstellar Gas and Cosmic Dust. The scientifIc programme consisted of a number of Topical Review papers introducing various as pects of these themes, supplemented by a large number of contributed papers (72 in to tal) presented either orally or as posters. Undoubtedly, the excellent poster sessions formed one of the highlights of the meeting.
