| Description |
Sunspots or dark regions of strong magnetic fields on the Sun are generated via magneto-hydrodynamic processes involving the cyclic generation of toroidal, sunspot fields from pre-existing poloidal fields and their eventual regeneration through a process, referred to as the solar dynamo. This leads to the well known periodic 11 year solar cycle with sunspot numbers climbing, at solar maximum, up to 200 in very active or strong solar cycles and dropping down, at solar minimum, to 20 or less sunspots during periods of solar minimum A study of solar photospheric fields and solar wind micro-turbulence in the inner-heliosphere suggests that we are headed towards a prolonged period of little/no sunspot activity similar to the most well-known Maunder minimum between 1645 and 1715. In this talk, I will present our analysis of solar observations which points to the unusual nature of the solar magnetic fields during the past 20 years. By analyzing solar photospheric magnetic fields as well as from radio astronomical observations using the IPS technique, we show that both solar magnetic fields as well as the interplanetary micro-turbulence levels have been steadily decreasing and by 2020, it will be similar to the Sun which has been observed during the grand minimum during 17th Century. Our studies of the ionospheric plasma cut-off frequency (fp) in cycle 23 indicates a significant lowering of fp, thereby opening up possibilities for ground based radio astronomy observations at the lowest frequencies (< 10 MHz) in the coming years.
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