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COLOQUIOS DEL DEPARTAMENTO DE FÍSICA FCEyN - UBA<br>
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<a href="http://coloquios.df.uba.ar/" target="_blank">http://coloquios.df.uba.ar/</a><br>
<br>
Charla, café y galletitas<br>
En el Aula Federman, 1er piso, Pabellón I,<br>
Ciudad Universitaria<br>
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Jueves 29 de septiembre, 14hs,<br>
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SPACE WEATHER<br>
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Ramon Lopez<br>
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Dept. of Physics, Univ. of Texas at Arlington<br>
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As our technological civilization becomes more dependent of space technology, we become more vulnerable to changes in the space environment in which that technology functions. These environmental changes are known as ?space weather.? In this talk I will discuss what drives space weather and how it affects human activities both in space and on the Earth. I will also discuss recent efforts by the Center for Integrated Space Weather Modeling to create physics-based numerical simulations of the magnetosphere to be used in forecasting space weather. <br>
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COLOQUIO EXTRA<br>
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Viernes 30/9, 11hs, Aula Federman<br>
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Negative effective magnetic pressure instability in turbulence simulations<br>
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Axel Brandenburg<br>
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NORDITA, Suecia<br>
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We present the first numerical demonstration of the negative effective<br style="padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;">
magnetic pressure instability in direct numerical simulations of<br style="padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;">
stably-stratified, externally-forced, isothermal hydromagnetic<br style="padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;">
turbulence. By the action of this instability, initially uniform<br style="padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;">
horizontal magnetic field forms flux concentrations whose scale is<br style="padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;">
large compared to the turbulent scale. We further show that the magnetic<br style="padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;">
energy of these large-scale structures is only weakly dependent on<br style="padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;">
the magnetic Reynolds number. Our results support earlier mean-field<br style="padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;">
calculations and analytic work which identified this instability.<br style="padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;">
Applications to the formation of active regions in the Sun are<br style="padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;">
discussed.<br>
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