Inversion of Plasmaspheric EUV Remote Sensing Data from the STP 72-1 Satellite

Observations of the extreme ultraviolet emission of helium ions at 30.4 nm can be used to study the global shape of the plasmasphere and its dynamical response to geomagnetic forcing. In order to retrieve number densities of plasmaspheric He+ from such observations, we have developed a new inversion technique based on discrete inverse theory, which uses the optical data to optimize a parameterized model of the He+ distribution. We apply this inversion technique to several orbits of data obtained from the Naval Research Laboratory extreme ultraviolet photometric experiment launched on the STP 72-1 satellite in October 1972. The inversion is limited to nighttime conditions where contamination from the topside ionosphere is minimal and where a simple parameterization of the He+ number density is applicable. We obtain excellent fits to the data; however, some of the retrieved model parameters have large uncertainties due to inadequate sampling of the plasmasphere. Our study shows that improved sampling using observations from different locations and view directions would significantly enhance the accuracy of the retrieved model parameters. Using a newly developed three-dimensional imaging tool to visualize the plasmaspheric regions being sampled remotely, we demonstrate that emission features observed from two of the STP 72-1 orbits originate beyond the plasmasphere. Estimated number densities of this feature are roughly consistent with observations of cold plasma seen at geosynchronous orbit by in situ experiments

Heliospheric Transport of Neutron-Decay Protons

We report on new simulations of the transport of energetic protons originating from the decay of energetic neutrons produced in solar flares. Because the neutrons are fast-moving but insensitive to the solar wind magnetic field, the decay protons are produced over a wide region of space, and they should be detectable by current instruments over a broad range of longitudes for many hours after a sufficiently large gamma-ray flare. Spacecraft closer to the Sun are expected to see orders-of magnitude higher intensities than those at the Earth-Sun distance. The current solar cycle should present an excellent opportunity to observe neutron-decay protons with multiple spacecraft over different heliographic longitudes and distances from the Sun.Comment: 12 pages, 4 figures, to be published in special issue of Solar Physic

Electric current circuits in astrophysics

Cosmic magnetic structures have in common that they are anchored in a dynamo, that an external driver converts kinetic energy into internal magnetic energy, that this magnetic energy is transported as Poynting fl ux across the magnetically dominated structure, and that the magnetic energy is released in the form of particle acceleration, heating, bulk motion, MHD waves, and radiation. The investigation of the electric current system is particularly illuminating as to the course of events and the physics involved. We demonstrate this for the radio pulsar wind, the solar flare, and terrestrial magnetic storms

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

Administration can be more patient-friendly, time-saving and cost-effective:Folfirinox treatment regimen for pancreas tumors can be more efficient

Door een kritische blik te werpen op het kuurschema van FOLFIRINOX is de Werkgroep Duurzaamheid en Doelmatigheid van de Nederlandse Vereniging Voor Medische Oncologie (NVMO) erin geslaagd dit schema patiëntvriendelijker, tijdbesparend en kosteneffectiever te maken. De aanbevelingen kunnen worden geëxtrapoleerd naar andere 5FU-bevattende chemokuren waaronder modified-FOLFIRINOX, FLOT, FOLFIRI, FOLFOX en FOLFOXIRI