Solar and Interplanetary Signatures of a Maunder-like Grand Solar Minimum around the Corner - Implications to Near-Earth Space
Abstract
Our study of a steady decline of solar high-latitude (?45?) photospheric magnetic fields for the past 20 years combined with the fact that cycle 24 is already past its peak, implies that high-latitude fields are likely to decline until ∼2020, the expected minimum of cycle 24.Also, interplanetary scintillation (IPS) observations, at 327 MHz, of solar wind micro-turbulence levels during 1983-2013, have shown a steady decline, in sync with the declining solar high-latitude fields. An estimateof both the heliospheric magnetic field (HMF) strength in 2020 and the floor value of the HMF, using the correlation between the polar field and the HMF at solar minimum, was found to be 4.0 (±0.6) nT and 3.2 (±0.4) nT, respectively. Using the estimated value of the HMF in 2020, the peak sunspot number for solar Cycle 25 was estimated to be 69 (±12). These results and the fact that solar magnetic fields continue to decline at present, begs the question as to whether we are headed towards a long period of very low sunspot activity similar to the well known Maunder minimum between 1645-1715. An assessment of possible impact of such a likely grand minimum on terrestrial ionospheric current systems, based on the one-to-one correlation of sunspot number and night time F-region maximum electron density, reveals that the period post 2020 will be useful for undertaking systematic ground based low-frequency radio astronomy observations, as the night time ionospheric cutoff-frequency could be well below 10 MHz.
- Publication:
-
Sun and Geosphere
- Pub Date:
- December 2015
- Bibcode:
- 2015SunGe..10..147J
- Keywords:
-
- Sun activity;
- Sun photosphere;
- solar wind;
- solar - terrestrial relations