A method is reported to determine, by data of the ground-based magnetic observations in polar cap, the quasi-sectorial (with periodicity from 7 to 27 days) SS* structures in the interplanetary magnetic field (IMF) BY component. The BY effect in the polar cap magnetic variations is revealed only under summer condition, when the high ionospheric conductivity ensures availability of ionospheric current systems, responsible for appropriate magnetic disturbances. It is shown that BY structures, reconstructed from the polar cap magnetic data during summer months, are in best conformity with actual variations of the IMF By component, measured onboard the ACE spacecraft in the Lagrange point L1. The reported method can be used for identification of the actual IMF BY component coupling with the magnetosphere. A great advantage of the method over other methods, based on the satellite measurements, is permanent, on-line available information on the real solar wind parameters affecting the magnetosphere. It implies that the BY IMF component, identified by the ground-based magnetic data, can be applied to verify and to validate information on solar wind parameters (https://omniweb.gsfc.nasa.gov/), obtained by distant monitors far upstream of the magnetosphere.
Author(s) Details:
O. A. Troshichev
Arctic and Antarctic Research Institute, Russia.
Recent global research developments in Identification of Quasi-Sectorial Structures in the Interplanetary Magnetic Field BY Component Using Ground-Based Polar Cap Magnetic Observations
1. Recent Geomagnetic Secular Variation from Swarm and Ground Observatories:
- In this study, researchers used data from the Swarm mission (over 2 years) and monthly means from 160 ground observatories to update the CHAOS time-dependent geomagnetic field model (CHAOS-6).
- CHAOS-6 provides information on time variations of the core-generated part of Earth’s magnetic field between 1999.0 and 2016.5.
- The study found evidence for positive acceleration of the field intensity in 2015 over a broad area around longitude 90°E, which was also observed at ground observatories.
- At the core surface, they mapped the secular variation (SV) up to at least degree 16.
- Surprisingly, little SV or secular acceleration (SA) occurred over the past 17 years in the southern polar region.
- The study also revealed a prominent planetary-scale, anti-cyclonic gyre centered on the Atlantic hemisphere based on quasi-geostrophic core flow inversion [1].
2. Heliocentric Distance and Solar Activity Dependence of Sustained Quasi-Radial Interplanetary Magnetic Field Occurrence:
- This research explored the occurrence of sustained quasi-radial interplanetary magnetic fields (IMFs) as a function of heliocentric distance and solar activity.
- The study investigated how IMF structures vary with distance from the Sun and under different solar conditions.
- Unfortunately, I don’t have direct access to the full paper, but you can find more details in the NASA Technical Report Server [2].
3. MagneToRE: Mapping the 3-D Magnetic Structure of the Solar Wind Using a Constellation of Spacecraft:
- Although not directly related to your query, this concept proposes a mission called MagneToRE.
- MagneToRE aims to reconstruct 3-D maps of the solar wind’s dynamic magnetic structure using a large constellation of in-situ spacecraft.
- The mission would provide valuable insights into the solar wind’s magnetic topology [2].
References
1. Finlay, C. C., Olsen, N., Kotsiaros, S., Gillet, N., & Tøffner-Clausen, L. (2016). Recent geomagnetic secular variation from Swarm and ground observatories as estimated in the CHAOS-6 geomagnetic field model. Earth, Planets and Space, 68, 1-18. https://earth-planets-space.springeropen.com/articles/10.1186/s40623-016-0486-1
2. Burkholder, B. L., Chen, L. J., Romanelli, N., Sibeck, D., Verniero, J., DiBraccio, G. A., … & Sarantos, M. (2023). Heliocentric Distance and Solar Activity Dependence of Sustained Quasi-radial Interplanetary Magnetic Field Occurrence. The Astrophysical Journal, 953(1), 85. https://earth-planets-space.springeropen.com/articles/10.1186/s40623-016-0486-1
3. Maruca BA, Agudelo Rueda JA, Bandyopadhyay R, Bianco FB, Chasapis A, Chhiber R, DeWeese H, Matthaeus WH, Miles DM, Qudsi RA, Richardson MJ, Servidio S, Shay MA, Sundkvist D, Verscharen D, Vines SK, Westlake JH and Wicks RT (2021) MagneToRE: Mapping the 3-D Magnetic Structure of the Solar Wind Using a Large Constellation of Nanosatellites. Front. Astron. Space Sci. 8:665885. doi: 10.3389/fspas.2021.665885
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