ISWI Newsletter - Vol.9 No.11
26 August 2017

Dear ISWI Participant:

If you would like to announce a space-weather-related event please send my way for distribution to all concerned.

CONTENTS OF THIS ISSUE

[1] News from India: "175 years of Colaba-Alibag pair of magnetic observatories" (read it)

[2] News regarding the recent total eclipse that passed over the USA (read it)

[3] Severe space weather chronicled in the Anglo-Saxon Chronicle (read it)

[1] "175 years of Colaba-Alibag pair of magnetic observatories"

Recently, we completed 175 years of Colaba-Alibag pair of magnetic observatories and had year long celebrations encompassing workshops, seminars etc. These year long celebrations concluded with a Valedictory function organized on 24^th February, 2017 at the Colaba observatory complex.

On this momentous occasion, we have compiled the summaries of the talks/seminars presented by eminent scientists throughout the year. We would like to have this published in the ISWI newsletter. A pdf copy of the same is attached for your perusal.

see the Proceedings of …:  

Send by Satyavir Singh

[2] Science News

A look at where the sun's surface meets its atmosphere could reveal the wind's origins

The sun can't keep its hands to itself. A constant flow of charged particles streams away from the sun at hundreds of kilometers per second, battering vulnerable planets in its path.

This barrage is called the solar wind, and it has had a direct role in shaping life in the solar system. It’s thought to have stripped away much of Mars’ atmosphere (SN: 4/29/17, p. 20). Earth is protected from a similar fate only by its strong magnetic field, which guides the solar wind around the planet.

But scientists don’t understand some key details of how the wind works. It originates in an area where the sun’s surface meets its atmosphere. Like winds on Earth, the solar wind is gusty ? it travels at different speeds in different areas. It’s fastest in regions where the sun’s atmosphere, the corona, is dark. Winds whip past these coronal holes at 800 kilometers per second. But the wind whooshes at only around 300 kilometers per second over extended, pointy wisps called coronal streamers, which give the corona its crownlike appearance. No one knows why the wind is fickle.

The August 21 solar eclipse gives astronomers an ideal opportunity to catch the solar wind in action in the inner corona. One group, Nat Gopalswamy of NASA’s Goddard Spaceflight Center in Greenbelt, Md., and his colleagues, will test a new version of an instrument called a polarimeter, built to measure the temperature and speed of electrons leaving the sun. Measurements will start close to the sun’s surface and extend out to around 5.6 million kilometers, or eight times the radius of the sun.

“We should be able to detect the baby solar wind,” Gopalswamy says.

Set up at a high school in Madras, Ore., the polarimeter will separate out light that has been polarized, or had its electric field organized in one direction, from light whose electric field oscillates in all sorts of directions. Because electrons scatter polarized light more than non-polarized light, that observation will give the scientists a bead on what the electrons are doing, and by extension, what the solar wind is doing ? how fast it flows, how hot it is and even where it comes from.

Gopalswamy and colleagues will also take images in four different wavelengths of light, as another measurement of speed and temperature. Mapping the fast and slow solar winds close to the surface of the sun can give clues to how they are accelerated.

For the rest of this article see: </article/2017-solar-eclipse-solar-wind>

Send by Nat Gopalswamy

[3] "Severe space weather chronicled in the Anglo-Saxon Chronicle"

See: Item from The Economist of 22 July 2017  

Send by G.Maeda

(1) Proceedings of "Geomagnetism, Earth, Moon & Sun" (GEMS) 4 329 KB pdf, 41 pages (click )

(2) Item from The-Economist of 22-July-2017 898 KB pdf, one page (click )

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