32 research outputs found
Recent Advances in Understanding Particle Acceleration Processes in Solar Flares
We review basic theoretical concepts in particle acceleration, with
particular emphasis on processes likely to occur in regions of magnetic
reconnection. Several new developments are discussed, including detailed
studies of reconnection in three-dimensional magnetic field configurations
(e.g., current sheets, collapsing traps, separatrix regions) and stochastic
acceleration in a turbulent environment. Fluid, test-particle, and
particle-in-cell approaches are used and results compared. While these studies
show considerable promise in accounting for the various observational
manifestations of solar flares, they are limited by a number of factors, mostly
relating to available computational power. Not the least of these issues is the
need to explicitly incorporate the electrodynamic feedback of the accelerated
particles themselves on the environment in which they are accelerated. A brief
prognosis for future advancement is offered.Comment: This is a chapter in a monograph on the physics of solar flares,
inspired by RHESSI observations. The individual articles are to appear in
Space Science Reviews (2011
TRADE AND THE ENVIRONMENTAL KUZNETS CURVE: IS SOUTHERN AFRICA A POLLUTION HAVEN?
Evidence that the environmental Kuznets curve (EKC) may be explained by trade patterns casts doubt on the oft-stated conclusion that economic growth automatically leads to environmental improvement. Trends in net exports as a proportion of consumption for both USA and UK trade with SACU were examined for various dirty industries. Some evidence of pollution haven effects is found, although a similar trend for clean industries suggests that this effect is weak. However, even a general shift in manufacturing industries from North to South (as opposed to a shift in specifically dirty industries) may explain the EKC to some extent. Copyright 2005 Economic Society of South Africa.