South American auroral reports during the Carrington storm

Auroral Disturbances During the January 10 , 1997 Magnetic Storm

Solar and auroral evidence for an intense recurrent geomagnetic storm during December in AD 1128

The earliest known drawing of sunspots appears in The Chronicle of John of Worcester, which was compiled in the first half of the twelfth century. In this medieval chronicle, the Latin text describing the sunspots is accompanied by a colourful drawing, albeit idealised, which shows the apparent positions and sizes of two sunspots on the solar disk. The date of this observation of sunspots from ...

Magnetotail energy dissipation during an auroral substorm

Violent releases of space plasma energy from the Earth's magnetotail during substorms produce strong electric currents and bright aurora. But what modulates these currents and aurora and controls dissipation of the energy released in the ionosphere? Using data from the THEMIS fleet of satellites and ground-based imagers and magnetometers, we show that plasma energy dissipation is controlled by ...

The size of the auroral belt during magnetic storms

Using the auroral boundary index derived from DMSP electron precipitation data and the Dst index, changes in the size of the auroral belt during magnetic storms are studied. It is found that the equatorward boundary of the belt at midnight expands equatorward, reaching its lowest latitude about one hour before Dst peaks. This time lag depends very little on storm intensity. It is also shown tha...

Chromosome Reports in South American Nicotianeae (solanaceae), with Particular Reference to Nierembergia

Chromosome counts and karyotype information from 41 populations of 20 species and 6 varieties of Nicotianeae (Solanaceae) from South America belonging to Bouchetia Dunal (x 5 8), Fabiana Ruiz & Pav. (x 5 9), Leptoglossis Benth. (x 5 10), Nierembergia Ruiz & Pav. (x 5 8, 9), and Petunia Juss. (x 5 7, 9) are given, including first reports from 14 taxa: F. densa Rémy, N. ericoides Miers, and P. pa...