Friday, May 1, 2015

NJIT's New Solar Telescope Unveils the Complex Dynamics of Sunspots' Dark Cores

Groundbreaking images of the Sun captured by scientists at NJIT’s Big Bear Solar Observatory (BBSO) give a first-ever detailed view of the interior structure of umbrae – the dark patches in the center of sunspots – revealing dynamic magnetic fields responsible for the plumes of plasma that emerge as bright dots interrupting their darkness. Their research is being presented this week at the first Triennial Earth-Sun Summit meeting between the American Astronomical Society’s Solar Physics Division and the American Geophysical Union’s Space Physics and Aeronomy section in Indianapolis, Ind.

The high-resolution images, taken through the observatory’s New Solar Telescope (NST), show the atmosphere above the umbrae to be finely structured, consisting of hot plasma intermixed with cool plasma jets as wide as 100 kilometers.
“We would describe these plasma flows as oscillating cool jets piercing the hot atmosphere. Until now, we didn’t know they existed.  While we have known for a long time that sunspots oscillate – moderate resolution telescopes show us dark shadows, or penumbral waves, moving across the umbra toward the edge of a sunspot – we can now begin to understand the underlying dynamics,” said Vasyl Yurchyshyn, a research professor of physics at NJIT and the lead author of two recent journal articles based on the NST observations.

Called spikes, the oscillating jets result from the penetration of magnetic and plasma waves from the Sun’s photosphere – the light-giving layer of its atmosphere – into the abutting chromosphere, which they reach by traveling outward along magnetic tubes that serve as energy conduits.  “This process can be likened to a blowhole at a rocky beach, where relentless onshore waves jet sea water high into the air,” Yurchyshyn said.

Sunspots are formed when strong magnetic fields rise up from the convection zone, a region beneath the photosphere that transfers energy from the interior of the Sun to its surface. At the surface, the magnetic fields concentrate into bundles, which prevent the hot rising plasma from reaching the surface. This energy deficit causes the magnetic bundles to cool down to temperatures about 1,000 degrees lower than their surroundings. They therefore appear darker against the hotter, brighter background.

“But the magnetic field is not a monolith and there are openings in the umbra from which plasma bursts out as lava does from a volcano’s side vents. These plumes create the bright, nearly circular patches we call umbral dots,” Yurchyshyn noted. “Sunspots that are very dark have strong magnetic fields and thus fewer openings.”

Compact groups of fast-changing sunspots create tension in their magnetic systems, which at some point erupt to relieve the stress. It is those eruptions that cause intense “space weather” events in the Earth’s magnetosphere affecting communications, power lines, and navigation systems.

“We had no sense of what happens inside an umbra until we were able to see it in the high-resolution images obtained with the world’s largest solar telescope. These data revealed to us unprecedented details of small-scale dynamics that appear to be similar in nature to what we see in other parts of the Sun,” Yurchyshyn said. “There is growing evidence that these dynamic events are responsible for the heating of coronal loops, seen in ultraviolet images as bright magnetic structures that jet out from the Sun’s surface. This is a solar puzzle we have yet to solve.”

Since it began operating in 2009, Big Bear’s NST has given scientists a closer look at sunspot umbrae, among other solar regions. It has also allowed them to measure the shape of chromospheric spectral lines, enabling scientists to probe solar conditions.

“These measurements tell us about the speed, temperature, and pressure of the plasma elements we are observing, as well as the strength and the direction of the solar magnetic fields,” said Yurchyshyn, who is also a distinguished scholar at the Korea Astronomy and Space Science Institute. “Thus we were able to find that spikes, or oscillating jets, are caused by chromospheric shocks, which are abrupt fluctuations in the magnetic field and plasma that constantly push plasma up along nearly the same magnetic channels.”

The study on umbral spikes was published in the Astrophysical Journal in 2014.

In a second paper published in the Astrophysical Journal in 2015, he is presenting another set of NST observations, taking a closer look at the sunspot oscillations that occur every three minutes and are thought to produce bright umbral flashes - emissions of plasma heated by shock waves.

The NST takes snapshots of the Sun every 10 seconds, which are then strung together as a video to reveal fast-evolving small explosions, plasma flows and the movement of magnetic fields. “We were able to obtain photographs of these flashes of unique clarity that allowed us to follow their development inside the umbra,” he said. Previously believed to be diffuse patches randomly distributed over the umbra, the researchers found their location is in fact not random. They mainly form along so-called sunspot umbral light bridges, which are very large openings in the sunspot magnetic fields that often split an umbra into two or more parts.

“Even more importantly, we found that umbral flash lanes tend to appear on the side of light bridges that face the center of the sunspot,” he added. “This finding is significant because it indicates that sunspot oscillations may be driven by one energy source located under the umbra. There are simulations that appear to reproduce what we have observed, which is very encouraging. We, as a community, are finally in the position to be able to directly compare the observations and the state-of-the-art simulation results, which is the key to making further progress in our field.”

To view more images, click here.

For further information, contact Tracey Regan at NJIT at or 201-388-0232 or Craig DeForest, AAS/SPD press officer, at or 303-641-5769.

Wednesday, April 29, 2015

Ham radio attempts to fill communication gaps in Nepal rescue effort

A nice write-up outlining how Ham Radio has once again provided vital lifelines of communication to the people of Nepal.

Amateur radio has stepped in to fill communication gaps in Nepal, which is struggling with power outages and a flaky Internet after a devastating earthquake on Saturday killed over 5,000 people. Though 99 persons have ham licenses in Kathmandu, about eight use high-frequency (HF) radios that can transmit long distances, while another 30 have very high frequency and ultra high frequency sets for local traffic, said Satish Kharel, a lawyer in Kathmandu, who uses the ham call signal 9N1AA. The hobbyist radio operators are working round-the-clock to help people get in touch with relatives, pass on information and alert about developing crises.

If you have 8 minutes, take a look at the video below from MikesMovies. This shows the real life emergency net that was developed to help with Nepalese communications.

Wednesday, March 4, 2015

Lab grown quartz crystals: How its done.

Following up on yesterdays post regarding the manufacture of radio crystals from natural quartz crystals, I was able to find this video from the AT&T archives showing the relatively new, at the time, method of growing quartz crystals in the laboratory.

The video, produced in 1962, shows first the frustrating failures and ultimately the ability of Bell Labs staff to reliably produce the invaluable quartz crystals.

Very little of the technology we value today would have been possible without the hard work and perseverance of these early pioneers.

Tuesday, March 3, 2015

Crystals Go to War - 1943

One of the things that always fascinated me about radio was the ability to take discrete components and craft something that could pluck invisible radio signals out of the air. Once I learned more about electronics, some of the magic was replaced by admiration for the many generations of engineers and experimenters that had developed the radio art. Until recently, the theory behind crystals had not solidified (crystallized?) in my mind and so they remained one of those "mysterious devices".

The following film, like most produced during WWII, is a thorough explanation of the history and technology behind radio crystals. It was produced at a period when crystals were instrumental in securing reliable communications between military units, saving lives and coordinating the moment of supplies, troops and equipment.

I hope you'll find it as interesting as I did.

Monday, July 21, 2014

Richardson "5" Update

Thanks to members of the excellent Antique Radio Forums and to a Mr Richardson (No relation, I think) I have found out more about the history of this receiver. It turns out that the set had been restored in the past from fairly sad shape after being purchased at an AWA swap meet in New York.

Underneath the top desk of the radio is the text "Oct.17.1996 Billy Richardson" which confirmed that the radio had originally passed though his hands while being brought back to life.

However I'll let Mr Billy Richardson tell the story in his own words:

I'm guilty of owning the Richardson "5", guys. It was in poor condition when I bought it in an AWA swap meet in New York way back there years ago. I restored it to the best of my ability to its original condition a few years later. It was not a restoration that had anything special going for it, so it was never shown in any of the contests around the country. It was working OK when I finished it, but I can understand why it doesn't work now.

To the best of my recollection, Richardson radios were first advertised as a superheterodyne kit. Their main feature was "self evident wiring", or something like that. Naturally. they didn't get away with selling a superheterodyne kit and the next and only ad I saw after that was a small one for the Richardson "5". It used the same type of wiring.

Here again I speak from a poor memory, but the wiring for this set is one long piece of rubber coated flexible wire. Along its entire length it has lugs that simply pierce the rubber cover to make an electrical contact. Not a good thing, because only one or two strands of wire may be making contact and a wee bit of oxidation is all it would take to break the connection. This was the case with the original wire, which was also hard and brittle. I replaced it with NOS flexible wire that looked exactly the same. The finished job is an ugly sight, just like the original. All the lugs are spaced an equal distant along the wire, regardless of how far it has to go to the next connection and most of the wire is too long for those connections. In other words, it's a jumbled up mess of wire and not something to be proud of.

I recognized the photo of this set immediately as being mine because of the label under the lid. There was enough of the original left to make a good copy and I thought the reproduction turned out real well.

Billy Richardson

Alan Douglas of the Antique Radio Forums found a clipping from Radio Retailer & Jobber Oct.1925 which told of Mr Richardson's exit from the Richardson Radio Corporation. Given the very short period where any advertisements were made it seems like this corporation didn't last very long at all, perhaps only a year or two at most. In the Radio News of 1925 the January issue has quite a large advertisement while the December issue has only the smallest note possible ... perhaps a sign that things were not going particularly well.

The only additional information I could find regarding either the Richardson Radio Corporation or Mr Richardson himself come from the clipping of the Princeton Alumni Weekly, August 1936.

Unfortunately it concerns what must have been his early death and does not specify the cause which would have been appropriate at the time.

The Class records with deep sorrow the death of our classmate, David W. Richardson, who died at his home in Mt. Kisko on July 16.
Dave spent the first two years out of college in the radio business. He helped organize WOR and was the president of the Richardson Radio, Inc.
He then entered the employ of Joseph P. Day and for five years was head of the private sales department. About a year ago he entered the brokerage business with Harris, Upham & Co. and on July 1 entered the employ of Eastman, Dillon & Co.
Dave was married in 1932 and has a son, David Welles Richardson, Jr. To his widow, his son, and his father we extend our deepest sympathy with the assurance that we will not soon forget him.
    For the Class of 1922
    William E. Stevenson, President
    G. M. L. LaBranche
    Hunt T. Dickinson
    Robert Buechner, Secretary.