Solar Wind Turbulence and the Role of Ion Instabilities

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Origins of the Ambient Solar Wind: Implications for Space Weather

The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal heating and the acceleration of the ambient solar wind. We also discuss where the community stands in its ability to forecast how variations in the solar wind (i.e., fast and slow wind streams) impact the Earth. Although the last few decades have seen significant progress in observations and modeling, we still do not have a complete understanding of the relevant physical processes, nor do we have a quantitatively precise census of which coronal structures contribute to specific types of solar wind. Fast streams are known to be connected to the central regions of large coronal holes. Slow streams, however, appear to come from a wide range of sources, including streamers, pseudostreamers, coronal loops, active regions, and coronal hole boundaries. Complicating our understanding even more is the fact that processes such as turbulence, stream-stream interactions, and Coulomb collisions can make it difficult to unambiguously map a parcel measured at 1 AU back down to its coronal source. We also review recent progress -- in theoretical modeling, observational data analysis, and forecasting techniques that sit at the interface between data and theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue connected with a 2016 ISSI workshop on "The Scientific Foundations of Space Weather." 44 pages, 9 figure

Effects of temperature on the establishment potential of the predatory mite Amblyseius californicus McGregor (Acari: Phytoseiidae) in the UK

Amblyseius californicus was introduced into the UK in the early 1990s as a biocontrol agent against glasshouse red spider mite Tetranychus urticae. This study investigated the effects of temperature on the establishment potential of A. californicus in the UK in the light of recent reports of their successful overwintering outside of glasshouse environments. The developmental thresholds were 9.9 and 8.6 degreesC respectively using simple and weighted linear regression. Using the day-degree requirement per generation calculated by weighted regression (143 day-degrees) in combination with climate data, it was estimated that up to seven generations would be possible annually outdoors in the UK. Non-diapausing adult females froze at -22 degreesC, with 100% mortality after reaching their freezing temperature. Up to 90% of mites died before freezing after short exposures to low temperatures. Significant acclimation responses occurred; 90% of acclimated individuals survived 26 days exposure at 0 degreesC and 11 days at -5 degreesC (acclimated mites were reared at 19 degreesC, 6L:18D followed by I week at 10 degreesC, 12L:12D). Non-diapausing adult females survived over 3 months outdoors in winter under sheltered conditions and oviposition was observed. The experimental protocol used in this study is discussed as a pre-release screen for the establishment potential of other Amblyseius species, and similar non-native biocontrol agents

Temporal resolution of cold acclimation and de-acclimation in the Antarctic collembolan, Cryptopygus antarcticus

The Antarctic collembolan, Cryptopygus antarcticus (Willem), can switch its supercooling point (SCP) between 'winter' and 'summer' modes of cold hardiness over a matter of hours. High resolution temporal scaling of the acquisition and loss of cold hardiness is undertaken by assaying changes in the proportion of animals freezing below −15 °C in response to cooling rate, acclimation temperature, and access to food and moisture. Rapid de-acclimation to the 'summer' modal state is readily achieved after 1–6 h in response to warming and access to food; however, rapid acclimation to the 'winter' modal state is only evident in response to slow cooling and narrow ranges of temperature (0–5 °C). The rapid loss of cold tolerance at higher temperatures with access to food, in particular, emphasizes this species' opportunistic responses to resource availability in the short polar summers. Cold hardiness is apparently more readily traded off against nutrient acquisition than vice versa in this maritime Antarctic species

The characteristics, behaviour and heterogeneous chemical reactivity of estuarine suspended particles

Incl. 4 reprintsSIGLEAvailable from British Library Document Supply Centre- DSC:D74928/87 / BLDSC - British Library Document Supply CentreGBUnited Kingdo