SCIENTIFIC AND TECHNICAL AEROSPACE REPORTS

A Biweekly Publication of the National Aeronautics and Space Administration
VOLUME 44, ISSUE 8 - April 21, 2006

92 SOLAR PHYSICS
Includes solar activity, solar flares, solar radiation and sunspots.

For related information see 93 Space Radiation.

20060010244 Washington Univ., United States

Investigation of Solar Radiation Properties at the Battleship Promontory Area, Antarctica

VanNortwick, Sara S.; Summer Student Research Presentations; August 2005, pp. 48; In English; See also 20060010186; NoCopyright; Available from CASI only as part of the entire parent document

JPL scientists in January 2005 visited the unique Battleship Promontory Area of the Antarctic Dry Valleys at 76 deg. 54min. S one of the few places on the Antarctic continent home to viable life. Cryptoendolithic microorganisms manage tosurvive on and inside rocks in Antarctica’s harsh conditions of extreme dryness and cold that are not So different from thepast and present conditions on Mars.We are investigating the physical properties of these biological creatures through analysisof optical spectra collected from a variety of rock samples over the deep UV, visible, and near-infrared regions with the intentof gaining key insights into the environmental factors that make such a habitat viable for life. The LabView programmingenvironment is equipped with the tools necessary to create an interface to visualize, manipulate, and normalize extensive rawreflectance and corresponding incident spectral data. We are determining the meaning of the colors observed and theirrelationship to the ability to acquire energy and investigating differences between the photosynthetic processes in full sunlightand diffuse/shadow lighting. Comparisons between spectral data collected in the field and from returned samples in the labvalidate the accuracy of our field collection methodology. Author

Antarctic Regions; Solar Radiation; Valleys

20060010445 Science Applications International Corp., San Diego, CA, USA

Ulysses Observations of the Magnetic Connectivity Between Coronal, Mass Ejections and the Sun

Riley, Pete; Goslin, J. T.; Crooker, . U.; The Astrophysical Journal; June 20, 2004; Volume 608, pp. 1100-1105; In EnglishContract(s)/Grant(s): NASW-02027; NAG5-10881; Copyright; Avail.: Other Sources

We have investigated the magnetic connectivity of coronal mass ejections (CMEs) to the Sun using Ulysses observationsof suprathermal electrons at various distances between 1 and 5.2 AU. Drawing on ideas concerning the eruption and evolutionof CMEs, we had anticipated that there might be a tendency for CMEs to contain progressively more open field lines, asreconnection back at the Sun either opened or completely disconnected previously closed field lines threading the CMEs. Ourresults, however, did not yield any discernible trend. By combining the potential contribution of CMEs to the heliospheric fluxwith the observed buildup of flux during the course of the solar cycle, we also derive a lower limit for the reconnection rateof CMEs that is sufficient to avoid the ‘flux catastrophe’ paradox. This rate is well below our threshold of detectability. Subjectheadings: solar wind - Sun: activity - Sun: corona - Sun: coronal mass ejections (CMEs) - On-line material: color figure Sun:magnetic fields. Author

Coronal Mass Ejection; Ulysses Mission; Solar Wind; Magnetic Fields; Heliosphere; Solar Cycles

20060010532 NASA Johnson Space Center, Houston, TX, USA

Simplified Solar Modulation Model of Inner Trapped Belt Proton Flux As a Function of Atmospheric Density

Wilson, Thomas L.; Lodhi, M. A. K.; Diaz, Abel B.; [2005]; 29 pp.; In English; Original contains color and black and whiteillustrations; Copyright; Avail.: CASI: A03, Hardcopy

No simple algorithm seems to exist for calculating proton fluxes and lifetimes in the Earth’s inner, trapped radiation beltthroughout the solar cycle. Most models of the inner trapped belt in use depend upon AP8 which only describes the radiationenvironment at solar maximum and solar minimum in Cycle 20. One exception is NOAAPRO which incorporates flight datafrom the TIROS/NOAA polar orbiting spacecraft. The present study discloses yet another, simple formulation forapproximating proton fluxes at any time in a given solar cycle, in particular between solar maximum and solar minimum. Itis derived from AP8 using a regression algorithm technique from nuclear physics. From flux and its time integral fluence, onecan then approximate dose rate and its time integral dose. It has already been published in this journal that the absorbed doserate, D, in the trapped belts exhibits a power law relationship, D = A(rho)(sup -n), whereAis a constant, rho is the atmosphericdensity, and the index n is weakly dependent upon shielding. However, that method does not work for flux and fluence.Instead, we extend this idea by showing that the power law approximation for flux J is actually bivariant in energy E as wellas density rho. The resulting relation is J(E,rho)approx.(sum of)A(E(sup n))rho(sup -n), with A itself a power law in E. Thisprovides another method for calculating approximate proton flux and lifetime at any time in the solar cycle. These in turn canbe used to predict the associated dose and dose rate. Author

Atmospheric Density; Inner Radiation Belt; Solar Activity Effects; Protons; Solar Cycles; Dosage; Fluence

20060011026 Science Applications International Corp., San Diego, CA, USA

Modeling Interplanetary Coronal Mass Ejections

Riley, Pete; Coronal and Stellar Mass Ejections IAU Symposium Proceedings (IAU 226); 2004; 15 pp.; In English; Copyright; Avail.: Other Sources

Modeling Interplanetary Coronal Mass Ejections Riley, Pete; Coronal and Stellar Mass Ejections IAU Symposium Proceedings (IAU 226); 2004; 15 pp.; In English; Copyright; Avail.: Other Sources Heliospheric models of Coronal Mass Ejection (CME) propagation and evolution provide an important insight into the dynamics of CMEa and are a valuable tool for interpreting interplanetary in situ observations. Moreover, they represent a virtual laboratory for exploring conditions and regions of space that are not conveniently or currently accessible by spacecraft. In this review I summarize recent advances in modeling the properties and evolution of CMEs in the solar wind. In particular, I will focus on: (1) the types of ICME models; (2) the boundary conditions that are imposed, (3) the role of the ambient solar wind; (4) predicting new phenomena; and (5) distinguishing between competing CME initiation mechanisms. I will conclude by discussing what topics will likely be important for models to address in the future. Author

Coronal Mass Ejection; Heliosphere; Solar Wind; Boundary Conditions

Source: NASA