PosterPDF Available

First results from the NASA WB-57 airborne observations of the Great American 2017 Total Solar Eclipse

Authors:

Abstract

Total solar eclipses present rare opportunities to study the complex solar corona, down to altitudes of just a few percent of a solar radius above the surface, using ground-based and airborne observatories that would otherwise be dominated by the intense solar disk and high sky brightness. Studying the corona is critical to gaining a better understanding of physical processes that occur on other stars and astrophysical objects, as well as understanding the dominant driver of space weather that affects human assets at Earth and elsewhere. For example, it is still poorly understood how the corona is heated to temperatures of 1-2 MK globally and up to 5-10 MK above active regions, while the underlying chromosphere is 100 times cooler; numerous theories abound, but are difficult to constrain due to the limited sensitivities and cadences of prior measurements. The origins and stability of coronal fans, and the extent of their reach to the middle and outer corona, are also not well known, limited in large part by sensitivities and fields of view of existing observations.Airborne observations during the eclipse provide unique advantages; by flying in the stratosphere at altitudes of 50 kft or higher, they avoid all weather, the seeing quality is enormously improved, and additional wavelengths such as near-IR also become available due to significantly reduced water absorption. For an eclipse, an airborne observatory can also follow the shadow, increasing the total observing time by 50% or more. We present the first results from airborne observations of the 2017 Great American Total Solar Eclipse using two of NASA's WB-57 research aircraft, each equipped with two 8.7" telescopes feeding high-sensitivity visible (green-line) and near-IR (3-5 µm) cameras operating at high cadence (30 Hz) with ~3 arcsec/pixel platescale and ±3 R_sun fields of view. The aircraft will fly along the eclipse path, separated by ~90 km, to observe a summed ~8 minutes of totality in both visible and NIR, enabling groundbreaking studies of high-speed wave motions and nanojets in the lower corona, the structure and extent of coronal fans, and constraints on a potential primordial dust ring around the Sun.
First results from the NASA WB-57 airborne observations of the Great American 2017 Total Solar Eclipse
A. Caspi, C. Tsang, C. DeForest, D.D. Durda, A.J. Steffl, SwRI
D.B. Seaton, CIRES, Univ. of Colorado & NOAA NCEI
P. Bryans, S. Tomczyk, J. Burkepile, P. Judge, NCAR/HAO
E.E. DeLuca, L. Golub, SAO
P.T. Gallagher, Trinity College Dublin
A. Zhukov, M. West, Royal Observatory Belgium
C.J. Mallini, T. Propp, J. Gascar, C. Klemm, M. Yates, D. Johnson, D. Del Russo, NASA JSC
J. Lewis, J. Wiseman, J. Collier, T.A. Casey, D. Darrow, SR
T. Parent, DynCorp & J. Warner, ViaSat
Overview Total solar eclipses present rare opportunities to study the complex solar corona,
down to altitudes of just a few percent of a solar radius above the surface, using ground-based and
airborne observatories that would otherwise be dominated by the intense solar disk and high sky
brightness. Studying the corona is critical to gaining a better understanding of physical processes
that occur on other stars and astrophysical objects, as well as understanding the dominant driver of
space weather that affects human assets at Earth and elsewhere. For example, it is still poorly
understood how the corona is heated to temperatures of 1-2 MK globally and up to 5-10 MK above
active regions, while the underlying chromosphere is 100 times cooler; numerous theories abound,
but are difficult to constrain due to the limited sensitivities and cadences of prior measurements.
The origins and stability of coronal fans, and the extent of their reach to the middle and outer
corona, are also not well known, limited in large part by sensitivities and fields of view of existing
observations.
Airborne observations during the eclipse provide unique advantages; by flying in the stratosphere
at altitudes of 50 kft or higher, they avoid all weather, the seeing quality is enormously improved,
and additional wavelengths such as near-IR also become available due to significantly reduced
water absorption. For an eclipse, an airborne observatory can also follow the shadow, increasing the
total observing time by 50% or more.
We present the first results from airborne observations of the 2017 Great American Total Solar
Eclipse using two of NASA's WB-57 research aircraft, each equipped with two 8.7" telescopes
feeding high-sensitivity visible (green-line) and near-IR (3-5 µm) cameras operating at high cadence
(30 Hz) with ~3 arcsec/pixel platescale and ±3 R_sun fields of view. The aircraft will fly along the
eclipse path, separated by ~90 km, to observe a summed ~8 minutes of totality in both visible and
NIR, enabling groundbreaking studies of high-speed wave motions and nanojets in the lower
corona, the structure and extent of coronal fans, and constraints on a potential primordial dust ring
around the Sun.
The Mission Two DyNAMITE-equipped WB-57 aircraft fly down the centerline of the eclipse,
at 50,000 ft. altitude. The WB-57 has two seats, occupied by a pilot and an operator. The aircraft are
spaced precisely so that Plane 2 enters the leading edge of the lunar shadow 10 s before Plane 1
exits the trailing edge. The overlap provides cross-calibration between the observation sets.
In the lead-up to totality, each operator monitors the disk of the Sun while DyNAMITE is pointed at
Mercury with recording activated. When the last Bailey's beads are observed, the operator retargets
DyNAMITE at the eclipsed Sun. When the first part of the photosphere emerges from behind the
Moon, the operator points DyNAMITE back to Mercury for 300 seconds. The instruments store
science-quality data on-board, but downlink quick-look video via satellite, as a live digital stream.
Coronal Waves, Jets, and Heating
The corona is mysteriously heated to over 1 million K. Two
candidate processes — magnetic reconnection and intense
sound waves modified by the magnetic field — should leave
distinct moving signatures in the corona, a “smoking gun”
for one or both theories. Our flight at 50,000 feet avoids
most atmospheric seeing, revealing coronal dynamics that
should help to constrain which processes may act to heat the
corona to such high temperatures.
Why is the corona “combed”?
Magnetic reconnection is difficult in the solar corona.
Magnetic field lines rise up from the churning photosphere
and stretch, twist, and knot, storing magnetic tension that is
released by reconnection. Simulations that capture the
difficulty of this process produce model coronas that are
tangled like dreadlocks, not combed like the actual corona,
thus tiny, ubiquitous, frequent reconnections must detangle
the corona continuously. We will search for the signs of these
tiny “nanojet” reconnections, throughout the corona.
quiet Sun, these are rooted within the vertices and
lanes defining the supergranular network. The
internetwork nonmagnetic chromosphere tends
to oscillate near 5 to 7 mHz in response to
convective driving. In the network itself, the
period shifts closer to 3 mHz (19). We observed
(Fig. 2) that the CoMP velocity power spectrum
peaks near 3.5 mHz, but relatively little of the
5-mHz power that dominates the internetwork
chromosphere was evident. Perhaps the waves
observed with CoMP originate from within the
chromospheric network that forms the footpoints
of the observed coronal loops. Recent work
demonstrated that p modes with frequencies
below the nominal acoustic cutoff frequency can
leak into the upper chromosphere along magnetic
field lines that are inclined to the gravitational
field, effectively reducing the cutoff frequency
(2024). The bulk of the 5-mHz power does not
penetrate the chromospheric canopy as compres-
sive oscillation modes (17,25,26), and so these
frequencies may not have a strong signature in
the corona. The waves we observed were only
those that could tunnelthrough the complex
chromosphere-transition region along the mag-
netic field lines and then be converted near the b=
1surface,wheretheplasmaforcebalancetran-
sitions from gas dominated to magnetic field
dominated to Alfvén modes. Unfortunately, the
conversion mechanism is not understood or easily
modeled, given the complex structure of the
interface between the chromosphere and corona.
We observe a dominanc e of upward over
downward wave propagation. Of all of the pixels
with acceptable errors, only ~1% had a negative
phase speed indicative of downward propagation.
This suggests that the waves are converted or
their energy is dissipated before they reach the
opposite footpoint. Given the large curvature of
the field lines over a typical wavelength, we would
expect that conversion of Alfvén to MA modes
would be efficient (27).
To eval uate the ability of the se waves to he at
the corona, we estimated the energy flux as
F
W
=rv
2
c
A
(3)
where ris the density, vis the velocity amplitude,
and c
A
is the Alfvén speed. Assuming a typical
value of the electron density of 10
8
cm
3
,we
estimate r~2×10
16
gcm
3
.Thefluxofenergy
propagating in the observed waves is then
F
W
~10ergcm
2
s
1
(0.01 W m
2
)(4)
Because we only observed the LOS velocity, this
estimate can be multiplied by a factor of 2. Even
so, the flux is 4 orders of magnitude too small to
balance the radiative losses even of the quiet solar
corona, ~100 W m
2
(28). The amplitude of the
Alfvén waves that we observed may be signifi-
cantly attenuated by averaging over many
unresolved waves within our spatial resolution
element and along the coronal LOS. The non-
thermal component of coronal emission line
widths is typically ~30 km s
1
and temporally
invariant, which, if due to unresolved Alfvén
waves, could provide a steady energy flux suf-
ficient to heat the corona.
These waves are ubiquitous in space and
time. This makes them ideal candidates for
coronal seismology(29,30), wherein the
Alfvén speed (wave phase speed) can be used
to measure the strength of coronal magnetic
fields through the relation:
cA¼B=ffiffiffiffiffiffiffi
4pr
pð5Þ
where Bis the magnetic field strength and ris the
plasma density. The phase speeds obtained in this
study are a projection onto the POS, that is, the
speed multiplied by sin(i), where iis the angle
between the LOS and the direction of wave
propagation. Then, given an estimate of the
density, the measured phase speeds provide an
Fig. 4. The results of the
CoMP travel-time analy-
sis in the 1.05 to 1.25
R
sun
range superimposed
on the SOHO/EIT image
from Fig. 1D. (Ato E)The
inferred wave travel time,
propagation angle, phase
speed, correlation length,
and correlation width,
respectively. Only points
where the error in the
phase speed from the
regression analysis is less
than 0.5 Mm s
1
and the
error in the propagation
angle is less than 10° are
plotted. (F)Thecompari-
son of the inferred wave
propagation angle and
the measured magnetic
field azimuth (Fig. 1F).
A CoMP Phase Travel-Time [s]
0 20 40 60 80 100
B CoMP Propagation Angle [Degrees]
-90 -60 -30 0 30 60 90
C CoMP Phase Speed [Mm/s]
-1000
-800
-600
-400
-200
0
200
Solar Y [arcsec]
0.00 1.00 2.00 3.00 4.00 5.00
D CoMP Correlation Length [Mm]
-1200 -1000 -800 -600 -400
Solar X [arcsec]
0 20 40 60 80 100
E CoMP Correlation Width [Mm]
-1200 -1000 -800 -600 -400
Solar X [arcsec]
0 4 8 12 16 20
-1000
-800
-600
-400
-200
0
200
Solar Y [arcsec]
-1000
-800
-600
-400
-200
0
200
Solar Y [arcsec]
-1000
-800
-600
-400
-200
0
200
Solar Y [arcsec]
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
XX
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XXX
X
X
X
X
X
X
X
X
X
X
X
X
X
XXX
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
XXX
X
X
X
X
X
XX
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
XXX
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
XX
X
X
X
XX
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
XX
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XXX
X
X
XXXX
X
X
X
XX
X
X
X
X
X
X
X
XXX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XXX
X
X
X
XXX
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
XX
X
XXXXX
X
XX
X
X
XXXX
X
X
X
X
X
X
X
X
X
X
XX
X
X
XX
X
X
X
X
XX
X
X
X
XX
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
XX
X
X
X
X
XX
X
X
X
X
X
XX
X
XX
X
X
XXX
X
X
X
X
XX
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
XX
X
X
XX
X
XX
X
X
XX
XXX
XX
X
X
X
XXX
X
X
X
X
X
X
X
X
X
X
XX
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XXX
X
X
X
X
X
X
X
X
X
XX
XX
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
XX
X
X
X
X
X
X
XX
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
XX
XX
XXX
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XXX
X
X
X
XX
X
X
XX
X
X
X
X
XXX
X
X
X
X
X
X
X
X
X
X
X
X
XXX
X
X
X
X
X
X
XXX
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XXX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
XX
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
XXX
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XXX
X
X
X
XX
X
X
X
X
X
X
X
X
XX
X
X
XXXX
XX
XX
X
XX X
XX
X
X
X
X
XX
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
XX
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
XXX
X
XXXX
XX
X
X
X
X
XX
X
X
X
X
XX
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
XX
X
XX
XX
X
XX
XX
X
XX
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
XX
XX
X
X
X
XX
X
XX
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
XX
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
XX
X
X
X
X
X
X
XX
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
XXX
X
X
X
XX
X
X
X
X
XX
X
X
X
XX
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
XXX
X
XXX
X
XXX
X
X
X
X
X
X
X
X
XX
X
X
X
X
XX
X
X
X
X
X
X
X
X
XX
X
XX
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
XXX
X
X
X
X
X
X
X
XXX
X
X
X
X
XX
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
XX
X
X
XX
X
XX
X
X
X
X
X
X
X
X
X
X
XX
X
XX
X
XX
X
X
X
X
X
X
X
X
XX
X
X
X
XXX
X
X
XX
X
X
XX
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
XX
X
X
XX
X
X
X
X
X
X
XX
X
X
XX
X
X
XXX
X
X
X
XX
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XXX
X
X
X
X
X
X
X
XX
X
XX
X
X
XX
XX
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
XXX
X
X
X
X
XXX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XXX
X
X
X
X
XX
X
X
X
XX
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
XX
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
XX
X
X
X
XX
X
X
XX
X
X
X
X
XX
X
X
X
XX
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
XX
X
X
XX
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
XX
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
XXX
X
XX
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
XX
X
XX
X
XX
X
X
X
X
XX
X
X
X
X
X
X
X
XX
X
XXX
X
X
X
X
XX
XX
X
X
X
X
XX
X
XX
X
X
X
X
X
X
X
X
X
X
X
XX
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
XX
X
XX
X
X
X
X
X
XX
X
X
XX
X
X
X
X
X
X
XX
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
XX
XX
X
XX
X
X
X
X
X
X
X
XX
XXX
X
X
X
X
XXX
XX
XX
X
X
X
X
X
X
X
X
X
XX
X
X
XX
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
XXX
X
X
X
X
X
X
X
X
X
XXX
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
XX
X
X
X
XX
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
XXX
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
XX
X
XXX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
XXX
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
XX
XXX
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
XX
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
XX
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
XXX
X
X
X
X
X
X
X
XX
X
X
X
XX
X
X
X
X
X
XXX
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
XX
XX
X
X
X
XX
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XXX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
XX
X
XX
X
XX
X
X
X
XX
X
XX
XX
X
X
X
X
X
X
X
X
XXX
X
X
X
X
X
X
X
XX
XX
X
XXX
X
X
X
X
XXX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
XXX
X
X
X
X
X
X
X
X
X
XX
X
X
XX
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
XXX
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XXX
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
XX
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
XX
X
X
X
X
X
X
X
X
XXXX
X
X
X
X
X
X
X
X
XX
X
XX
X
X
X
X
X
X
X
X
X
X
X
XX
XX
X
XX
X
X
XX
X
X
X
XXX
X
X
XX
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
XX
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
XX
X
XXX
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XXX
X
X
X
XX
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
XXX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
XX
XX
X
X
XX
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
XX
XXX
X
X
X
X
X
XXX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XXXXX
XX
X
X
X
XXX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XXXX
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
XX
XXXXX
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
XXXXX
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
XXX
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XXXX
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
XX
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
XXX
XX
X
X
XX
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
XX
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
XXX
XX
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
F Comparing Azimuth and Wave Angles
-50 0 50
Magnetic Azimuth [Degrees]
-50
0
50
Wave Propagation Angle [Degrees]
-1000
-800
-600
-400
-200
0
200
Solar Y [arcsec]
www.sciencemag.org SCIENCE VOL 317 31 AUGUST 2007 1195
REPORTS
on July 18, 2017 http://science.sciencemag.org/Downloaded from
Coronal Fans: mysterious boundaries
Wide-field extreme-ultraviolet (EUV) images have revealed
fanlike structures at the boundaries of coronal holes. These
fans are brighter than expected in EUV far from the Sun, and
may be related to the formation of the slow solar wind. By
merging our eclipse coronal images in the visible green
emission line, with images from the GOES-16/SUVI and
PROBA-2/SWAP EUV imagers, we will determine the
currently-unknown density and temperature structure of
these enigmatic structures, and hopefully determine their
relationship to the solar wind around them.
Above Studies by Tomczyk et al. (2007) using the CoMP
instrument revealed signatures of waves propagating
through the corona. Right Simulations using fluxon modeling
(DeForest & Kankelborg, 2007) suggest the coronal magnetic
field would be highly tangled if some process did not act to
smooth it. Far Right Coronal fan and pseudostreamers are
clearly visible to heights >2 solar-radii in this 171 Å image
from the new Solar Ultraviolet Imager on NOAAs GOES-16
spacecraft.
The DyNAMITE Instrument The Day/Night Airborne Motion Imager for Terrestrial
Environments (DyNAMITE) was built by Southern Research to image rockets and other airborne
objects. It is a stabilized, agile, steerable platform with two telescopic channels: visible and infrared
(IR). DyNAMITE is mounted in a modified nose of the WB-57 aircraft. The IR channel is specifically
designed for remote thermal imaging. The cameras have in-flight-controllable zoom lenses, and
acquire images at 30 frames per second.
2017 August 21 Eclipse Results
Top Left 3–5 µm medium wave infrared image of the solar corona, with 3 arcsec per pixel
platescale, obtained with a FLIR SC8303 camera with 8.95 inch custom lens. Note the
prominence at approximately 3 o’clock. Fixed pattern noise has not been removed. !
Bottom Left Composite image of the corona in a 100 Å bandpass centered on the Fe XIV
green line at 5303 Å. The overlay shows Fe XII at 195 Å from the SUVI imager on NOAAs
GOES-16 spacecraft at the time of the eclipse. The green filter image helps to reject skyglow
and F-corona, to enhance the contrast in the K- and E-coronae. The image is obtained with a
Ikegami HDL-F30 broadcast high-definition camera which has been calibrated in the lab.
Images are obtained at 30 Hz to allow us to characterize high frequency dynamics in the
corona. The sun is offset in the frame to achieve 4 solar-radius extent to the west, platescale is
3 arcsec per pixel. The image has been cropped, no calibration has been applied.!
Bottom Right Unsharp masking reveals polar plumes, loops, and streamers. The banding and
speckled structure is the result of compression and downsampling for the engineering data and
is not expected to occur in the losslessly compressed scientific data.
Calibration
Observations
Coronal
Observations
Mercury
Observations
ResearchGate has not been able to resolve any citations for this publication.
ResearchGate has not been able to resolve any references for this publication.