https://link.springer.com/article/10.1007%2Fs11207-021-01774-9
Hajra, R. Weakest Solar Cycle of the Space Age: A Study on Solar Wind–Magnetosphere Energy Coupling and Geomagnetic Activity. Sol Phys 296, 33 (2021). https://doi.org/10.1007/s11207-021-01774-9
Abstract
Solar Cycle 24, from December 2008 to December 2019, is recorded to be the weakest in magnitude in the space age (after 1957). A comparative study of this cycle with Solar Cycles 20 through 23 is presented. It is found that Solar Cycle 24 is not only the weakest in solar activity, but also in average solar wind parameters and solar wind–magnetosphere energy coupling. This resulted in lower geomagnetic activity, lower numbers of high-intensity long-duration continuous auroral electrojet (AE) activity (HILDCAA) events and geomagnetic storms. The Solar Cycle 24 exhibited a ≈54 – 61% reduction in HILDCAA occurrence rate (per year), ≈15 – 34% reduction in moderate storms (−50 nT≥Dst>−100 nT), ≈49 – 75% reduction in intense storms (−100 nT≥Dst>−250 nT) compared to previous cycles, and no superstorms (Dst≤−250 nT). Implications of the solar and geomagnetic weakening to space weather science and operations are discussed.
...
3. Conclusions
The present work indicates a strong impact of the solar activity cycle magnitude on the so-
lar wind–magnetosphere energy coupling and resultant geomagnetic activity. The weakest
magnitude of SolarCycle24 isfound to be associated with an overall reduction in en-
ergy coupling and reduced numbers of magnetic storms and HILDCAAs. The stronger the
storms, the stronger the reduction in number with no superstorms in Solar Cycle 24. This
has a great impact on the cosmic ray shielding. As shown in the present work, reduced solar
activity makes the near-Earth space exposed to a higher flux of cosmic rays. This can have
important effects on manned missions at low Earth orbit or to the Moon and Mars.
Recent studies predict the solar activity entering in a period of grand minimum (e.g.
Wang,2017; Jiang and Cao,2018; Upton and Hathaway,2018; Gonçalves, Echer, and Frigo,
2020, and references therein). This may lead to a much lower solar wind energy input in the
magnetosphere and a further decrease in geomagnetic activity events. This has large impacts
on space weather effects and technological applications
Hajra, R. Weakest Solar Cycle of the Space Age: A Study on Solar Wind–Magnetosphere Energy Coupling and Geomagnetic Activity. Sol Phys 296, 33 (2021). https://doi.org/10.1007/s11207-021-01774-9
Abstract
Solar Cycle 24, from December 2008 to December 2019, is recorded to be the weakest in magnitude in the space age (after 1957). A comparative study of this cycle with Solar Cycles 20 through 23 is presented. It is found that Solar Cycle 24 is not only the weakest in solar activity, but also in average solar wind parameters and solar wind–magnetosphere energy coupling. This resulted in lower geomagnetic activity, lower numbers of high-intensity long-duration continuous auroral electrojet (AE) activity (HILDCAA) events and geomagnetic storms. The Solar Cycle 24 exhibited a ≈54 – 61% reduction in HILDCAA occurrence rate (per year), ≈15 – 34% reduction in moderate storms (−50 nT≥Dst>−100 nT), ≈49 – 75% reduction in intense storms (−100 nT≥Dst>−250 nT) compared to previous cycles, and no superstorms (Dst≤−250 nT). Implications of the solar and geomagnetic weakening to space weather science and operations are discussed.
...
3. Conclusions
The present work indicates a strong impact of the solar activity cycle magnitude on the so-
lar wind–magnetosphere energy coupling and resultant geomagnetic activity. The weakest
magnitude of SolarCycle24 isfound to be associated with an overall reduction in en-
ergy coupling and reduced numbers of magnetic storms and HILDCAAs. The stronger the
storms, the stronger the reduction in number with no superstorms in Solar Cycle 24. This
has a great impact on the cosmic ray shielding. As shown in the present work, reduced solar
activity makes the near-Earth space exposed to a higher flux of cosmic rays. This can have
important effects on manned missions at low Earth orbit or to the Moon and Mars.
Recent studies predict the solar activity entering in a period of grand minimum (e.g.
Wang,2017; Jiang and Cao,2018; Upton and Hathaway,2018; Gonçalves, Echer, and Frigo,
2020, and references therein). This may lead to a much lower solar wind energy input in the
magnetosphere and a further decrease in geomagnetic activity events. This has large impacts
on space weather effects and technological applications
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