Posts
Today’s Sun (artificially-colored in red) seen at the 304-angstrom wavelength (Extreme Ultraviolet, or EUV), as viewed by the Solar Dynamics Observatory (SDO), by the Atmospheric Imaging Assembly (AIA).
At this wavelength, at a wavelength not seen by the un-aided eye, we can see the Sun through the 30.4 nm (304 A) filter. This Extreme Ultraviolet (EUV) waveband is used to monitor the chromosphere and lower transition region. It is useful to see plasma and filament activity, including filamet eruptions and coronal mass ejections (CMEs).
The image is a “false color image’, meaning that observed data are in a range outside of what human eyes can see, so the data are digitally recast into colors that emphasize physically important features. This view is created from data gathered by the Solar Dynamics Observatory (SDO) satellite that flies above Earth’s atmosphere in an inclined geosynchronous orbit.
Emissions captured in this image come from helium (He), the second most abundant element in the solar atmosphere. Singly ionized Helium (He II) emits Extreme Ultraviolet (EUV) light when heated to temperatures of ~70,000 deg K. In the upper solar atmosphere the temperatures are so high that most chemical elements have lost many of their electrons. The remaining electron, which is still attached to the atom, emits EUV radiation in narrow wavebands or lines when it is in an excited state.
The 30.4 nm filter (also called channel or bandpass) is dominated by emissions from singly (once) ionized helium which has missing 1 electron–He II. The roman numeral descriptor is consistent with spectral notation: the level of ionization for a given roman numeral is one unit larger that the actual number of missing electrons. The temperatures associated with this level of ionization is range from 6 x 10^4 K to 8 x 10^4 K.
The bright regions in this image correspond to regions of closed magnetic field loops that trap the hot, emitting plasma. Large bright regions are often called active regions. The dark regions correspond to cooler temperatures and possibly to locations where magnetic field lines open into the heliosphere, and thus, do not trap hot plasma.
View live data and images at http://SunSpotWatch.com
-
-
-
-
-
-
- +
-
-
-
-
-
BOOK SALE: Space Weather and Sun Science - get these from Amazon, and help us stay online!
NOTICE: When you buy this (or any item after starting with this link), you are helping us keep our SunSpotWatch.com and other resources "on the air” (up and running!). In other words, you are helping the entire community. So, check out this book:
Here is the link to Amazon: http://g.nw7us.us/fbssw-aSWSC
-
-
-
-
-
-
- +
-
-
-
-
-
Don’t forget: You can also get the space weather and radio propagation self-study course, today. Visit http://nw7us.us/swc for the latest sale and for more information!
-
-
-
-
-
-
- +
-
-
-
-
-
Visit our live space weather and radio propagation web site, at: http://SunSpotWatch.com
See the live aurora mapping is at http://ift.tt/2lYUS2h
If you are on Twitter, please follow these two users:
We’re on Facebook: http://NW7US.us/swhfr
from Ham Radio Times http://ift.tt/2vcznjf
via IFTTT
No comments:
Post a Comment