Distributed Arrays of Small Instruments for Solar-Terrestrial Research Report of a Workshop (2006) / Chapter Skim
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2 Compelling Science
2 Compelling Science
Pages 10-25
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From page 10... ...
Science drivers discussed at the workshop span the coupled system from Earth's atmosphere, through the complex interactions of the magnetosphere with both the lower regions and the interplanetary environment, to the ultimate drivers of space weather in solar activity and variability. MAGNETOSPHERE-IONOSPHERE What Is the Configuration of the M-I-T System That Is Most Vulnerable to Space Weather?
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FIGURE 2.1 An example of a magnetometer array. The Mid-continent Magnetoseismic Chain is a National Science Foundation project that conducts research in magnetospheric sounding using ground magnetic field observations.
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Strong magnetospheric electric fields are generated as storm-injected energetic particles fill the enhanced ring current. These subauroral electric fields erode the plasmasphere boundary layer, producing plasmaspheric drainage plumes that carry the high-altitude material toward the dayside magnetopause.
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Strong subauroral electric fields perturb the outer plasmasphere, and large, variable, magnetic perturbations give rise to ground-induced currents that have the potential for disrupting terrestrial electrical power grids. It is important to understand fully the subauroral electric and magnetic disturbances that result from the ring current.
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monitor the electric fields and plasma redistribution pattern across this region. FIGURE 2.2.1 Graphic from the SuperDARN home page on the World Wide Web that shows the fields of view of the northern SuperDARN radars.
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Role of DASI Workshop participants considered the application of distributed instrument arrays, including monitors of the aurora and associated currents, ionospheric density and conductivity, electric fields, and thermospheric winds, to address the questions listed above. Such arrays could include an extension of THEMIS instrumentation (see Box 2.3.)
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At onset, the aurora intensifies and expands, and the magnetic field caused by the ionospheric current intensifies. FIGURE 2.3.1 The rapid evolution of the aurora across the midnight sector (see illustration at |
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, then the resulting disturbance may be lessened. Unknowns The evolution of plasma processes and the system response throughout space weather events may depend in poorly understood ways on the initial conditions of the geospace system.
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This heating causes the atmosphere to lift, increasing drag on satellites. During magnetic substorms all of the above elements are very important, since large electric fields, combined with large particle precipitation, increase the frequency of collision between the neutrals and ions.
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Related Questions · What is the effect of thermosphere-ionosphere variability during quiescent periods on the development of space weather disturbance events?
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The most dramatic new insights into solar interior dynamics in the near future will likely come from the emerging field of local helioseismology, which has already provided unprecedented insight into the structure underlying active regions and large-scale flow patterns such as meridional circulation. Imaging of magnetic activity on the farside of the Sun using a local technique called acoustic holography can provide information on the generation and evolution of active regions and up to 2 weeks' advance notice of the formation of regions likely to produce space weather phenomena such as flares and coronal mass ejections.
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A flare is a rapid localized increase in radiative output, particularly at shorter wavelengths, generated by a process of magnetic reconnection that converts magnetic energy to heat. The various forms of solar activity do not occur in isolation as separate events, but rather tend to occur in concert because of changes in the state of the magnetic field.
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This technique is called helioseismology, because of its similarities to terrestrial seismology, and is at the heart of the program carried out by the Global Oscillations Network Group (GONG)
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To address solar activity, continuous measurements are needed, from active regions to global scales, of plasma and magnetic field properties from the photosphere through the corona. Role of DASI Understanding the origins of solar activity and monitoring it in detail as it occurs require continuous time coverage.
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structure of the heliospheric magnetic field near Earth. Role of DASI Neutrons and muons are secondary products of >1-GeV particles in Earth's atmosphere.
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IPS sites arranged at different longitudes around the globe will enable continuous time coverage of solar events. Multiple antennas at each site will provide more velocity measurements toward more sources.
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