The FRS nomination of Sir Prafulla C. Ray and the correspondence of N. R. Dhar.

Sir Prafulla Chandra Ray (1861-1944) was the first Indian chemist to achieve high international reputation. Originally trained at the University of Edinburgh, he worked for many years at Presidency College in Calcutta and then at Calcutta University. He built up a remarkable school of chemical research by attracting many outstanding students to work with him and published about 150 papers-many of them in leading British and German journals.

Origin of grand minima in sunspot cycles.

One of the most striking aspects of the 11-year sunspot cycle is that there have been times in the past when some cycles went missing, a most well-known example of this being the Maunder minimum during 1645-1715. Analyses of cosmogenic isotopes ((14)C and (10)Be) indicated that there were about 27 grand minima in the last 11,000 yrs, implying that about 2.7% of the solar cycles had conditions appropriate for forcing the Sun into grand minima.

Why does the sun's torsional oscillation begin before the sunspot cycle?

Although the Sun's torsional oscillation is believed to be driven by the Lorentz force associated with the sunspot cycle, this oscillation begins 2-3 yr before the sunspot cycle. We provide a theoretical explanation of this with the help of a solar dynamo model having a meridional circulation penetrating slightly below the bottom of the convection zone, because only in such dynamo models does the strong toroidal field form a few years before the sunspot cycle and at a higher latitude.

Predicting solar cycle 24 with a solar dynamo model.

Whether or not the upcoming cycle 24 of solar activity will be strong is being hotly debated. The solar cycle is produced by a complex dynamo mechanism. We model the last few solar cycles by "feeding" observational data of the Sun's polar magnetic field into our solar dynamo model.

Explaining the latitudinal distribution of sunspots with deep meridional flow.

Sunspots, dark magnetic regions occurring at low latitudes on the Sun's surface, are tracers of the magnetic field generated by the dynamo mechanism. Recent solar dynamo models, which use the helioseismically determined solar rotation, indicate that sunspots should form at high latitudes, contrary to observations. We present a dynamo model with the correct latitudinal distribution of sunspots and demonstrate that this requires a meridional flow of material that penetrates deeper than hitherto believed, into the stable layers below the convection zone.