Introduction to Special Issue on high speed solar wind streams and geospace interactions (HSS–GI)

Denton, M. H.; Borovsky, Joseph E.; Horne, Richard B.; McPherron, R. L.; Morley, S.; Tsurutani, B. T.

doi:10.1016/j.jastp.2008.09.019

Cited by 13 publications

(9 citation statements)

References 33 publications

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“…The arrival of high‐speed solar wind streams (HSSs) at the Earth's magnetosphere initiates numerous physical processes, including (1) a sudden onset of magnetospheric convection (e.g., McPherron and Weygand [2006] and compare Figure 5), (2) enhanced density, heating, and transport in the plasma sheet [e.g., Borovsky et al , 1998; Lavraud et al , 2006; Denton and Borovsky , 2008], (3) enhanced particle precipitation [ Longden et al , 2008], (4) flux dropouts/recovery of outer radiation belt electrons [e.g., Paulikas and Blake , 1979; O'Brien et al , 2001; Borovsky and Denton , 2009a], (5) the formation of long‐lived plasmaspheric drainage plumes [ Borovsky and Denton , 2006b, 2008], and (6) an increase in ionospheric heating and the occurrence of F region storms [ Denton et al , 2009b; Sojka et al , 2009]. Many of these processes are interlinked [e.g., Tsurutani et al , 2006; Kavanagh and Denton , 2007; Denton et al , 2009a]. For example, the onset of convection (process 1) causes plasma from the outer plasmasphere to be stripped away into a plasmaspheric plume (process 5), which is implicated in the loss of relativistic electrons from the outer radiation belt (process 4) [ Borovsky and Denton , 2009a].…”

Section: Evolution Of the Outer Electron Radiation Belt During High‐smentioning

confidence: 99%

A density‐temperature description of the outer electron radiation belt during geomagnetic storms

2010

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[1] Bi-Maxwellian fits are made to energetic-electron flux measurements from seven satellites in geosynchronous orbit, yielding a number density (n) and temperature (T) description of the outer electron radiation belt. For 54.5 spacecraft years of measurements the median value of n is 3.7 Â 10 À4 cm À3 , and the median value of T is 148 keV. General statistical properties of n, T, and the 1.1-1.5 MeV flux F are investigated, including localtime and solar-cycle dependencies. Using superposed-epoch analysis where the zero epoch is convection onset, the evolution of the outer electron radiation belt through high-speed-stream-driven storms is investigated. The number-density decay during the calm before the storm, relativistic-electron dropouts and recoveries, and the heating of the outer electron radiation belt during storms are analyzed. Using four different ''triggers'' (sudden storm commencement (SSC), southward interplanetary magnetic field (IMF) portions of coronal mass ejection (CME) sheaths, southward-IMF portions of magnetic clouds, and minimum Dst) a selection of CME-driven storms are analyzed with superposed-epoch techniques. For CME-driven storms, only a very modest density decay prior to storm onset is found. In addition, the compression of the outer electron radiation belt at the time of SSC is analyzed, the number-density increase and temperature decrease during storm main phase are characterized, and the increase in density and temperature during storm recovery phase is determined. During the different phases of storms, changes in the flux are sometimes in response to changes in the temperature, sometimes to changes in the number density, and sometimes to changes in both. Differences are found between the density-temperature and flux descriptions, and it is concluded that more information is available using the density-temperature description.Citation: Denton, M. H., J. E. Borovsky, and T. E. Cayton (2010), A density-temperature description of the outer electron radiation belt during geomagnetic storms,

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Section: Evolution Of the Outer Electron Radiation Belt During High‐smentioning

confidence: 99%

A density‐temperature description of the outer electron radiation belt during geomagnetic storms

2010

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“…The D ST index typically displays a shallow minimum during an HSS‐driven storm, the relatively low magnitude of which indicates a much less intense ring current than that during a typical CME‐driven storm. On occasion, the low‐intensity D ST signature of some HSS‐driven storms has caused them to be overlooked in storm studies; an omission which has been referred to as the “ D ST mistake” [ Denton et al ., ].…”

Section: Data Sets and Hss Identificationmentioning

confidence: 99%

Inner magnetospheric heavy ion composition during high‐speed stream‐driven storms

et al. 2013

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[1] Ion composition data, taken by the Combined Release and Radiation Effects Satellite Magnetospheric Ion Composition Spectrometer instrument, are investigated across eight high-speed solar wind-stream-driven storms (HSSs) during 1991. The HSSs are identified using solar wind data from OMNI alongside geomagnetic indices, and the behavior of ions in the energy range 31.2-426.0 keV is investigated. A case study of the single HSS event that occurred on 30 July 1991 is performed, and superposed epoch analyses of five events are conducted. The data show evidence of a local minimum (dropout) in the flux and partial number density of ionic species H + , He + , He ++ , and O + close to the onset of magnetospheric convection. The flux and number density rapidly fall and then recover over a period of hours. The initial rapid recovery in number density is observed to consist primarily of lower-energy ions. As the number density reaches its maximum, the ions show evidence of energization. Heavy ion-to-proton ratios are observed to decrease substantially during these HSS events.Citation: Forster, D. R., M. H. Denton, M. Grande, and C. H. Perry (2013), Inner magnetospheric heavy ion composition during high-speed stream-driven storms,

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“…Historically, these intervals have been defined using the Dst index (Piddington, ; Loewe & Prölss, ). Since Dst effectively measures the energy content of the ring current (Sckopke, ), whether it is an appropriate measure for organizing or predicting other space weather disturbances has been discussed (Borovsky & Shprits, ; Denton et al, ). Operational space weather forecast centers use the Kp index (Mayaud, ) to define geomagnetic storm levels (Sharpe & Murray, ).…”

Section: Introductionmentioning

confidence: 99%

Challenges and Opportunities in Magnetospheric Space Weather Prediction

Morley

2020

Space Weather

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Space Weather is the study of the dynamics of the coupled Solar‐Terrestrial environment, as these dynamics impact technological systems and human activity. This paper reviews a selection of the advances, challenges, and new opportunities for magnetospheric space weather, and while the focus is on specific phenomena, many other aspects of space weather will have similar challenges and needs. As a scientific field with direct applications, the field of space weather is partly driven by imperatives from both policy and operations. We provide an introduction to some of the context in which the field exists and discuss how this might shape future developments and norms within the space weather enterprise. We briefly examine benchmarking, as a policy and operationally driven activity, as it provides immediate societal relevance and an opportunity to stretch scientific understanding. As numerical space weather prediction now becomes routine, and exascale computing is in the near future, we identify challenges relating to computational expense and big data, capturing and accounting for uncertainties, and specification of boundary conditions. Here, as with the observations supporting numerical space weather prediction, the key challenge lies in extending the lead time of predictions. We also discuss the role of data, particularly in regard to model validation and empirical modeling. Due to the growing societal impact of space weather, we also examine the relationships between space weather and its terrestrial counterpart and look at the importance of continuous evaluation, monitoring progress in predictive capability, and communication with researchers, forecasters, and end users.

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Introduction to Special Issue on high speed solar wind streams and geospace interactions (HSS–GI)

Cited by 13 publications

References 33 publications

A density‐temperature description of the outer electron radiation belt during geomagnetic storms

A density‐temperature description of the outer electron radiation belt during geomagnetic storms

Inner magnetospheric heavy ion composition during high‐speed stream‐driven storms

Challenges and Opportunities in Magnetospheric Space Weather Prediction

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