25 Years of Self-organized Criticality: Concepts and Controversies

Introduced by the late Per Bak and his colleagues, self-organized criticality (SOC) has been one of the most stimulating concepts to come out of statistical mechanics and condensed matter theory in the last few decades, and has played a significant role in the development of complexity science. SOC, and more generally fractals and power laws, have attracted much comment, ranging from the very positive to the polemical. The other papers (Aschwanden et al. in Space Sci. Rev., 2014, this issue; McAteer et al. in Space Sci. Rev., 2015, this issue; Sharma et al. in Space Sci. Rev. 2015, in preparation) in this special issue showcase the considerable body of observations in solar, magnetospheric and fusion plasma inspired by the SOC idea, and expose the fertile role the new paradigm has played in approaches to modeling and understanding multiscale plasma instabilities. This very broad impact, and the necessary process of adapting a scientific hypothesis to the conditions of a given physical system, has meant that SOC as studied in these fields has sometimes differed significantly from the definition originally given by its creators. In Bak’s own field of theoretical physics there are significant observational and theoretical open questions, even 25 years on (Pruessner 2012). One aim of the present review is to address the dichotomy between the great reception SOC has received in some areas, and its shortcomings, as they became manifest in the controversies it triggered. Our article tries to clear up what we think are misunderstandings of SOC in fields more remote from its origins in statistical mechanics, condensed matter and dynamical systems by revisiting Bak, Tang and Wiesenfeld’s original papers

Solar and heliospheric influences on the Earth's weather and climate

International audienceThis special issue on ‘Solar and heliospheric influences on the Earth's weather and climate' explores the physical mechanisms which causally link space weather and space climate to the Earth's weather and climate and tackles their mutual coupling through top–down/bottom–up pathways in a broadly holistic and interdisciplinary way. The first section of this special issue is concerned with energetic charged particles precipitating into the Earth's atmosphere, where the particles ionise molecules, with distinct effects on the global atmospheric electric circuit and the microphysical properties of aerosols, clouds, and the most important greenhouse gas: water vapour. The second part emphasises the tropospheric response upon solar variability, which may be amplified by non-linear processes in the climate system, and the electromagnetic connection between the troposphere and interplanetary space through sprites and man-made electromagnetic pollution of the near Earth space environment. The papers collected in this special issue were presented during a session denoted ‘Solar and heliospheric influences on the Earth's weather and climate' at the 1st General Assembly of the European Geosciences Union in Nice, France, 25–30 April 2004. This session grew out of the activities of the scientific network SPECIAL (Space Processes and Electrical Changes Influencing Atmospheric Layers), initiated by Michael J. Rycroft and supported by the European Science Foundation (ESF), which attracted a large number of contributions from the atmospheric and space science community. The management of the resulting special issue was based on the particularly strong commitment of the authors, reviewers, the publisher, and the Editorial team, all of which worked very hard towards a fast production of this booklet. The Editorial team is particularly indebted to the very timely and thoughtful responses of the reviewers, who made substantial contributions to improve the original outline of the submitted manuscripts

古代东南越人原始崇拜初探

本文研究春秋战国时际至汉初东南区越人的图腾崇拜和信仰． 第一部分以考古材料为主，结合文献记载，民族志材料，考证东南区越人鸟.蛇图腾崇拜之信仰的形成，特殊崇拜形式。以及由鸟.蛇崇拜结合别民族文化因素而衍生出来的其他信仰． 第二部分从东南区越人所处的生态，经济生产方式及历史传统文化表现出的心理倾向三方面探讨东南区越人鸟。蛇图腾崇拜形成背景。 第三部分从东南越人同其他民族文化比较的角度来分析东南越人原始崇拜若干特点。 第四部分结合东南越人的历史，对其崇拜和信仰在部族社会生活、经济生产、文化艺术等方面所具有的功能作一粗浅的总结。 根据考古出土物及文献材料．本文在探讨古代东南越人崇拜和信仰时侧...学位：文学硕士院系专业：人文学院人类学研究所_民族学学号：YL000073

eHEROES: where Space Weather and Communication meet

status: publishe

25 Years of Self-organized Criticality: Space and Laboratory Plasmas

Studies of complexity in extended dissipative dynamical systems, in nature and in laboratory, require multiple approaches and the framework of self-organized criticality (SOC) has been used extensively in the studies of such nonequilibrium systems. Plasmas are inherently nonlinear and many ubiquitous features such as multiscale behavior, intermittency and turbulence have been analyzed using SOC concepts. The role of SOC in advancing our understanding of space and laboratory plasmas as nonequilibrium systems is reviewed in this article. The main emphasis is on how SOC and related approaches have provided new insights and models of nonequilibrium plasma phenomena. Among the natural plasmas the magnetosphere, driven by the solar wind, is a prominent example and extensive data from ground-based and space-borne instruments have been used to study phenomena of direct relevance to space weather, viz. geomagnetic storms and substorms. During geomagnetically active periods the magnetosphere is far from equilibrium, due to its internal dynamics and being driven by the turbulent solar wind, and substorms are prominent features of the complex driven system. Studies using solar wind and magnetospheric data have shown both global and multiscale features of substorms. While the global behavior exhibits system-wide changes, the multiscale behavior shows scaling features. Along with the studies based on observational data, analogue models of the magnetosphere have advanced the understanding of space plasmas as well as the role of SOC in natural systems. In laboratory systems, SOC has been used in modeling the plasma behavior in fusion experiments, mainly in tokamaks and stellarators. Tokamaks are the dominant plasma confinement system and modeling based on SOC have provided a complementary approach to the understanding of plasma behavior under fusion conditions. These studies have provided insights into key features of toroidally confined plasmas, e.g., the existence of critical temperature gradients above which the transport rates increase drastically. The SOC models address the transport properties from a more general approach, compared to those based on turbulence arising from specific plasma instabilities, and provide a better framework for modeling features such as superdiffusion. The studies of space and laboratory plasmas as nonequilibrium systems have been motivated by features such as scaling and critical behavior, and have provided new insights by highlighting the properties that are common with other systems.Fil: Sharma, A. Surjalal. University Of Maryland; Estados UnidosFil: Aschwanden, Markus J.. Lockheed Martin Corporation; Estados UnidosFil: Crosby, Norma B.. Belgian Institute For Space Aeronomy; BélgicaFil: Klimas, Alexander J.. Nasa Goddard Space Flight Center; Estados UnidosFil: Milovanov, Alexander V.. Russian Academy Of Sciences. Space Research Institute; Rusia. Enea Centro Ricerche Frascati; ItaliaFil: Morales, Laura Fernanda. Canadian Space Agency; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sanchez, Raul. Universidad Carlos Iii de Madrid. Instituto de Salud; EspañaFil: Uritsky, Vadim. Nasa Goddard Space Flight Center; Estados Unido

Services for Space Mission Support Within The ESA Space Situational Awareness Space Weather Service Network

Spacecraft operations are by nature complex and every satellite's operational environment poses a range of potential risks, often a unique combination for a given orbit. The implications of interruptions of operations, data transfer and service provision, are serious, both in terms of cost and capability, thus it is imperative to mitigate against all operational risks to the fullest extent possible. In the frame of its Space Situational Awareness (SSA) programme, the European Space Agency (ESA) is establishing a Space Weather Service Network to support end-users, in a wide range of affected sectors, in mitigating the effects of space weather on their systems, reducing costs and improving reliability. This service network is currently in a test and validation phase and encourages user engagement and feedback. The network is organised around five Expert Service Centres (ESCs) focusing on Solar Weather, Heliospheric Weather, Space Radiation Environment, Ionospheric Weather and Geomagnetic Conditions. Each ESC is connecting different expert groups, federating their space weather products, and ensuring the quality and consistency of the provided information. The service network also includes a central Data Centre and the SSA Space Weather Coordination Centre (SSCC). In this presentation we give an overview of the current status of the network (http://swe.ssa.esa.int/), the targeted end-user groups and Expert Service Centres with a focus on the space community