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| The Hi-resolution Coronal Imager full resolution image shown here is from the solar active region outlined in the AIA image (upper left). Several partial frame images are shown including a potion of a filament channel (upper center/right), the braided ensemble (left, second from top), an example of magnetic recognition and flaring (left, third from top), and fine stranded loops (left, bottom). These Hi-C images are at a resolution of 0.2" or 90 miles. This resolution is the equivalent of resolving a dime from 10 miles away. [Image credit: NASA] |
Researchers were able
to witness this phenomenon in the highest resolution images ever taken of the
solar corona. These images were obtained by the agency's High Resolution
Coronal Imager (Hi-C) telescope, which was launched from the White Sands
Missile Range in New Mexico in July 2012.
"Scientists have
tried for decades to understand how the sun's dynamic atmosphere is heated to
millions of degrees," said Hi-C principal investigator Jonathan Cirtain, a
heliophysicist at NASA's Marshall Space Flight Center in Huntsville, Ala.
"Because of the level of solar activity, we were able to clearly focus on
an active sunspot, and obtain some remarkable images. Seeing this for the first
time is a major advance in understanding how our sun continuously generates the
vast amount of energy needed to heat its atmosphere."
The telescope, the
centerpiece of a payload weighing 464 pounds and measuring 10-feet long, flew
for about 10 minutes and captured 165 images of a large, active region in the
sun's corona. The telescope acquired data for five minutes, taking one image
every five seconds. Initial image sequences demonstrated the evolution of the
magnetic field and showed the repeated release of energy through activity seen
on the sun at temperatures of 2 million to 4 million degrees.
Many of the stars in
the universe have magnetic fields. The evolution of these fields is used to
explain the emission of the star and any events like flares. Understanding how
the magnetic field of the sun heats the solar atmosphere helps explain how all
magnetized stars evolve.
These observations
ultimately will lead to better predictions for space weather because the
evolution of the magnetic field in the solar atmosphere drives all solar
eruptions. These eruptions can reach Earth's atmosphere and affect operations
of Earth-orbiting communication and navigation satellites.
The images were made
possible by a set of innovations on Hi-C's optics array. The telescope's
mirrors were approximately 9 1/2 inches across. New techniques for grinding the
optics and polishing the surfaces were developed for the mirrors. Scientists
and engineers worked to complete alignment of the mirrors, maintaining optic
spacing to within a few ten-thousandths of an inch.
"The Hi-C
observations are part of a technology demonstration that will enable a future
generation of telescopes to solve the fundamental questions concerning the
heating of the solar atmosphere and the origins of space weather, "said
Jeffrey Newmark, sounding rocket program scientist at NASA Headquarters in
Washington.
Hi-C's resolution is
about five times finer than the imaging instrument aboard NASA's Solar Dynamics
Observatory (SDO) launched in February 2010 to study the sun and its dynamic
behavior. The Hi-C images complement global sun observations continuously taken
by SDO.
NASA's suborbital
sounding rockets provide low-cost means to conduct space science and studies of
Earth's upper atmosphere. The Hi-C mission cost about $5 million.
"This suborbital
mission has given us a unique look into the workings of the sun addressing a
major mystery in nature. Hi-C has demonstrated that high value science can be
achieved on a small budget," said John Grunsfeld, associate administrator
for NASA's Science Mission Directorate (SMD) in Washington. "NASA's
sounding rocket program is a key training ground for the next generation of
scientists, in addition to developing new space technologies."