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- Title
Transpolar Convection and Magnetospheric Ring Current Relations: Real‐Time Applications of the Polar Cap (PC) Indices.
- Authors
Stauning, Peter
- Abstract
The present study confirms the validity of previously derived relations between the polar cap (PC) indices and the ASY‐H and the Dst and SYM‐H ring current indices when used in real‐time applications. PC indices are here derived in simulated real‐time (SRT) versions by using past data only from −40 days up to current time in the construction of the quiet reference levels (QDCs) for the magnetic data. From analyses spanning a decade (2009–2018), equivalent ASY‐H index values were derived from a linear relation with SRT PCN (North) and PCS (South) indices combined to form the non‐negative PCC indices. For the cases of strong magnetic storms (Dst(peak)< −100 nT), the equivalent ASY‐H indices were found to agree well with reported (real) ASY‐H index values. The SRT PCC indices, furthermore, have been used in a PC‐based source function to derive equivalent values of the total ring current indices Dst (or SYM‐H) up to 1 h ahead of time. With integration of the source function throughout a decade (2009–2018) with no attachment to reported Dst values, the SRT equivalent Dst indices display close agreement with real Dst index values. The applied method could be used without modifications to generate PC index values and derived ASY‐H and Dst (or SYM‐H) index values in real‐time space weather applications. Plain Language Summary: Polar Cap (PC) indices are derived from the magnetic variations related to the plasma drift over the polar caps generated by the interaction with the solar wind. The present work believed to be the first of its kind presents applications of PC indices developed in a reliable real‐time version. The PC indices may be used to monitor the solar wind electric fields considered responsible for the transfer of solar wind energy to the magnetosphere. The solar wind energy supply power to disturbances such as auroral current systems responsible for upper atmosphere heating and fast magnetic variations that may induce harmful currents in power grids near the auroral regions. The PC indices are used here to derive intensities of the ring currents of oppositely drifting positive and negative ions encircling the Earth near equator at distances of 4–6 earth radii. The present work demonstrates the close relation between polar cap and ring currents and supports the use of real‐time PC indices for space weather monitoring. Key Points: Reference level construction for real‐time polar cap (PC) indicesRelations between ring current ASY‐H indices and real‐time PC index valuesDerivation of ring current Dst and SYM‐H index values from real‐time PC indices
- Subjects
IONOSPHERIC electromagnetic wave propagation; ATMOSPHERIC electromagnetic wave propagation; IONOSPHERE; RING currents; MAGNETOSPHERIC currents
- Publication
Space Weather: The International Journal of Research & Applications, 2021, Vol 19, Issue 7, p1
- ISSN
1539-4956
- Publication type
Article
- DOI
10.1029/2020SW002702