Disturbed space environment may have been related to pager satellite failure

Baker, D. N.; Allen, J. H.; Kanekal, S. G.; Reeves, G. D.

doi:10.1029/98eo00359

Cited by 133 publications

(72 citation statements)

References 6 publications

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“…The relativistic electrons in the outer belt can be especially hazardous to spacecraft systems [e.g., Baker et al, 1998;Baker, 2001], and thus, accurate forecasting of relativistic electron flux is important for mitigating the associated risk to spacecraft operations. This paper discusses a new, empirical model that forecasts the logarithm of daily averaged, 1.1 --1.5 MeV electron flux at geosynchronous orbit (GEO).…”

Section: Discussionmentioning

confidence: 99%

Space Weather Quarterly Volume 5, Issue 3, 2008

2008

Space Weather Quarterly

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Educating 2S pa c e W e at h e r Q ua r t e r ly (see L. Lanzerotti, Space Weather, 6, S01002, doi:10.1029/2007SW000385, 2008. However, I am happy to note that the Space Studies Board of the U.S. National Research Council took an important step toward setting a framework for achieving some of these "reliable estimates" in a workshop held in late May in Washington, D. C. The meeting drew active participation from the academic research community and major government agencies in the National Space Weather Program (http://www.nswp .gov), as well as a significant number of commercial interests large and small. These latter included enterprises that use space weather information for design decisions and/or successful operations, as well as vendors of space weather products and services. EDITORThe workshop explored several issues related to the economics of space weather. For example, the climatology of space radiation is essential for the design of the long-lived communications satellites that occupy geosynchronous orbit. Current radiation climate models are 30 or more years old and do not reflect major discoveries of the past few decades. Closely tied to this is the absence of reliable information on the statistics of the radiation environment: Are there upper limits to expected flux values, and should designs be based upon such limits (if they are known) or on some lesser (and less expensive to implement) values? What are the design and operations costs for not knowing this information? What are the costs to achieve such information and thus to make future design processes more robust?The policy-oriented participants provided many provocative (and productive) insights on space weather and its economic effects. These included discussions of the prioritization of risks (including space weather) to a business or government activity, as well as the perception of risks to the public. An important realization stressed by several participants was the central role of the complex electricity grid across the nation, which underpins essentially all contemporary technologies. What is the risk of a collapse of a major part of the grid from a space weather event? Equally important, can this risk and its economic consequences be examined without causing a "sky is falling" mentality? Where does a space weather risk to the grid rank with respect to other risks, natural and man-made?This workshop was an important initial forum for assembling a diverse and engaged group of individuals and organizations centrally involved with space weather concerns. The discussions illuminated numerous unresolved engineering, science, and policy issues related to the economics of space weather. However, solid economic information was often lacking in the discussions, partly because of the absence of such data and partly because of proprietary concerns. I hope the National Research Council can use this initial endeavor as the beginning of a more extensive process to delve into space weather economics. editorial W W W. ag u . o r g / j o u r n a l S ...

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Section: Discussionmentioning

confidence: 99%

Space Weather Quarterly Volume 5, Issue 3, 2008

2008

Space Weather Quarterly

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“…As the magnetic fields of solar active regions erupt into the solar atmosphere, an array of fascinating and energetic phenomena transpire to produce variability of the solar output: Large fluctuations occur in the ultraviolet and X-ray output, solar flares (Figure 2) produce very rapid changes at short wavelengths that are sometimes accompanied by bursts of energetic protons at the Earth, and intrinsically magnetic events known as coronal mass ejections, or CMEs (Plate 1), may disrupt the interplanetary magnetic field, causing geomagnetic storms. Societial consequences of solar magnetic activity are widespread, including disruption of communications, radiation hazards for astronauts and for unmanned spacecraft [Baker et al, 1998], and likely influences on terrestrial climate [Frieman et al, 1994]. …”

Section: Solar Magnetism and Solar Variabilitymentioning

confidence: 99%

Remote sensing of solar magnetic fields

Lites¹

2000

Reviews of Geophysics

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Abstract. New techniques for remote sensing of solar magnetic fields now provide measures of the magnetic field vector within the solar atmosphere with high angular resolution and high precision. These measurements have enabled a much improved physical understanding of magnetic processes and phenomena in the solar atmosphere, processes that drive the variability of the Sun's radiative and particulate output. The new techniques are reviewed here in the context of the scientific advances they have fostered. Emphasis is given to techniques for inferring the field vector. The quantitative nature of the information needed to explore the solar phenomena sharply constrains the needed precision and angular resolution of the observations. These requirements are reviewed here, along with an assessment of how future improvements in observing capabilities will address these requirements. One may also attribute much of the recent advance in our understanding of solar magnetic fields to ongoing progress in techniques for analysis of the polarization measurements that underlie solar magnetometry. The status and prospects of analysis techniques are also reviewed. The Large-Scale Solar Magnetic Field and the Solar DynamoThe 11-year cycle of solar activity is certainly the most widely recognized mode of solar variability. In fact, it represents a 22-year magnetic cycle: Two l 1-year cycles are required to restore the dominant magnetic polarity near the poles of the Sun. This cycle is dramatically revealed in the synoptic "magnetic butterfly diagram" of Figure 3, which shows the evolution of the large-scale solar magnetic field during the past two sunspot cycles. This map is assembled from individual solar "magnetograms" of the full solar disk similar to that shown in Figure 4. The behavior of the solar magnetic field at these global scales reflects the working of the solar dynamo [Roberts, 1994]. The dynamo, which is believed to be operative near the base of the solar convective layer (or about one third the solar radius below the surface), results from the combined action of solar rotation and convective flows within the highly conducting solar plasma. The solar dynamo problem represents one of the major challenges of astrophysics: Dynamos are responsible for magnetic activity in a range of stellar types, and some stars sustain magnetic activity cycles that are much more energetic than that of the Sun. Figure 3 contains a wealth of information on the nature of the dynamo as reflected in the behavior of the magnetic fields as they penetrate the solar surface, for example, the latitude and phase in the cycle of the emergence of fields and the motions of large-scale unipolar

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“…One of the first who drew attention to the hazards inherent in the outer radiation belt enhancement was D.N. Baker [Baker et al, 1987;Baker, 2000Baker, , 2001Baker et al, 1998Baker et al, , 2001]. In our country, a large series of research works on the effect of energetic particle fluxes on spacecraft operation was carried out at the Institute of Physics of the Earth of the Russian Academy of Sciences by V. Romanova et al, 2005;Pilipenko et al, 2006.;.…”

Section: Introductionmentioning

confidence: 99%