Illus. Solar Phys. Terms
Illustrations of Solar Physics Terminology
I've started this collection of illustrations of
solar terminology, but can't devote much time to it.
The ultimate goal: a compendium of "archetypal"
images, suitable for use in research talks by working
solar physicists.
All contributions are welcome (credit will be given), as multiple entries
for each topic would be ideal.
Emphasis is on the images, not the definitions of terms.
I welcome any suggestions for improvement; please e-mail me your
comments!
- cavity:
a region of hot coronal plasma, associated with a filament or
filament channel; magnetic field of cavity is thought to be
topologically isolated from surrouding corona; cavity plasma
is thought to be much hotter but less dense than filament it contains
-
A 752 kB mpeg movie of a cavity w/filament,
associated with the CME of 04 Jan. '02 below
(swiped from the
Hot Shots from SOHO page)
- coronal mass ejection (CME): magnetized plasma ejected from Sun,
usu. taken to have been a prominence/filament before ejection;
typical params: speed = ~400 km/s; mass = 1045 g;
size = ~RSun = ~7 x 105 km
-
An APOD image of a CME from taken with SoHO LASCO
-
A 245 kB mpeg movie of a CME, associated with the filment eruption of
04 Jan. '02 below
(swiped from the
Hot Shots from SOHO page)
- emerging flux:
- movie from SXT Nuggets, Dec. 22, 2000
-- and the full
Nugget
- filament: a long, thin, cool collection of magnetized plasma
above the photospheric surface, when seen on the Sun's disk
(a "filament" differs from a "prominence" only in viewing angle
-- latter viewed over limb);
ejected filaments are called coronal mass ejections
-
TRACE image of an erupting filament, from APOD
-
A 752 kB mpeg movie of a filament eruption (w/nice cavity!),
associated with the CME of 04 Jan. '02 above
(swiped from the
Hot Shots from SOHO page)
- hale's law: tendency of leading (in sense of Sun's rotation)
polarity in active region fields to differ in N & S hemispheres
- A SoHO MDI full-disk image of longitudinal
magnetic fields, 7 July 2000
- joy's law: tendency of the tilt of axis of
bipolar active region sunpots to increase with increasing latitude
- GIF of fig. 5 (p.168) from
Hale, Ellerman, Nicholson, & Joy, in ApJ,v.49, p.153
- Kolmogorov spectrum: -5/3 power law dependence on
turbulent velocity field's energy spectrum E(k) on wave number
k; energy is input at scale k0
and dissipated at scale knu (this is also a good
definition of the spectral index:
the value of the exponent in a power-law relation,
equal to 5/3 in this case)
- sketch of a Kolmogorov-like energy spectrum
- linking number: net number of times loops of
two "directed lines" link each other, with sign determined by
``right hand rule'' sense of linkage:
if the thumb of one's right hand points in the direction of line 2
where line 2 intersects the surface interior to line 1,
the linkage will be positive if the fingers of the right hand point in the
direction of line 1, and negative
if they point in the direction opposite line 1.
(This sketch provided courtesy of
Mitch Berger.)
- sketch of a flux tubes w/linking number of -3
- black & white (bitmap) postscript version of same
-Effect/Babcock Mechanism:
shear from differential rotation turns initially poloidal field lines into
toroidal field lines.
(Sketches taken from TRACE's page,
"the Sun's Magnetic Personality.")
- initial, poloidal field
- midpoint of field evolution
- final, toroidal field
- prominence: a filament (see above) viewed above the limb
- supergranule: convective cells tens of Mm (or tens of arc sec)
in diameter
- A SoHO MDI high res. image of
supergranular disruption of active region magnetic fields, 7 July 2000
- turbulent diffusion: dispersion of magnetic flux in turbulent
velocity fields, as in the solar convection zone
- A SoHO MDI high res. image of
supergranular disruption of active region magnetic fields, 7 July 2000
- sigmoid: An "S"-shaped or "backwards-S"-shaped
collection of coronal loops, often seen in SXT.
- Two beautiful SXT sigmoids.
The first was seen on 1998 June 7; observers predicted an eruption,
which then occurred on June 8 and produced a halo CME.
The same region subsequently formed another sigmoid, and another eruption
occurred on June 19. (Image swiped from Dr. Charles Kankelborg.)
Links to Other Solar Physics Imagery, Glossaries, and Info
- Lockheed-Martin's Space/Aerospace Lab (LMSAL) has compiled a nice page,
"Images of Our Magnetic Star," which has images suitable for conveying
complex ideas, including the Sun's cyclic activity, and imaging in different
wavelengths.
Very many good images here.
-
The Sun Acts Up is collection of images and sketches
maintained by the good people at NASA's Goddard Space Flight Center,
including images of dramatic events such as CME's & flares.
Very many good images here.
-
The Sun: A Pictorial Introduction:
A Slide Set by P. Charbonneau and O.R. White has slides and
detailed explanations covering many basic ideas in the field.
It's an excellent introduction to the "zoology" of solar phyics.
- Hugh Hudson has compiled sketches from the solar physics
literature into a
Grand Archive of Flare and CME Cartoons.
-
Our star, the Sun
is a collection of facts, images, and sketches
from the SoHO E.P.O. program. (See also their
FAQ page and
Not-so FAQ page.
- This
GLOSSARY OF SOLAR-TERRESTRIAL TERMS, maintained by NOAA,
is primitive but very comprehensive: it's got a lot
that no other glossary does.
- This
ON-LINE GLOSSARY OF SOLAR-TERRESTRIAL TERMS,
also maintained by NOAA, is fairly comprehensive.
- There is yet another
Solar Physics Glossary, this one maintained by NASA employees.
- David Knisely has compiled a
Glossary of H-Alpha terms, as part of his "Complete H-Alpha Handbook."
- Bill Arnett has compiled a nifty page entitled simply,
"The Sun."
- I have compiled approximate solar parameters ("bag numbers")
from the literature in a
web-viewable look-up table, or
postscript format for printing.