 |
|
Scientists discover surprise in Earth's upper atmosphere
September 10, 2009UCLA atmospheric scientists have discovered a previously unknown basic mode of energy transfer from the solar wind to the Earth's magnetosphere. The research, federally funded by the National Science Foundation, could improve the safety and reliability of spacecraft that operate in the upper atmosphere.
"It's like something else is heating the atmosphere besides the sun. This discovery is like finding it got hotter when the sun went down," said Larry Lyons, UCLA professor of atmospheric and oceanic sciences and a co-author of the research, which is in press in two companion papers in the Journal of Geophysical Research.
The sun, in addition to emitting radiation, emits a stream of ionized particles called the solar wind that affects the Earth and other planets in the solar system. The solar wind, which carries the particles from the sun's magnetic field, known as the interplanetary magnetic field, takes about three or four days to reach the Earth. When the charged electrical particles approach the Earth, they carve out a highly magnetized region - the magnetosphere - which surrounds and protects the Earth.
Charged particles carry currents, which cause significant modifications in the Earth's magnetosphere. This region is where communications spacecraft operate and where the energy releases in space known as substorms wreak havoc on satellites, power grids and communications systems.
The rate at which the solar wind transfers energy to the magnetosphere can vary widely, but what determines the rate of energy transfer is unclear.
"We thought it was known, but we came up with a major surprise," said Lyons, who conducted the research with Heejeong Kim, an assistant researcher in the UCLA Department of Atmospheric and Oceanic Sciences, and other colleagues.
"This is where everything gets started," Lyons said. "Any important variations in the magnetosphere occur because there is a transfer of energy from the solar wind to the particles in the magnetosphere. The first critical step is to understand how the energy gets transferred from the solar wind to the magnetosphere."
The interplanetary magnetic field fluctuates greatly in magnitude and direction.
"We all have thought for our entire careers - I learned it as a graduate student - that this energy transfer rate is primarily controlled by the direction of the interplanetary magnetic field," Lyons said. "The closer to southward-pointing the magnetic field is, the stronger the energy transfer rate is, and the stronger the magnetic field is in that direction. If it is both southward and big, the energy transfer rate is even bigger."
However, Lyons, Kim and their colleagues analyzed radar data that measure the strength of the interaction by measuring flows in the ionosphere, the part of Earth's upper atmosphere ionized by solar radiation. The results surprised them.
"Any space physicist, including me, would have said a year ago there could not be substorms when the interplanetary magnetic field was staying northward, but that's wrong," Lyons said. "Generally, it's correct, but when you have a fluctuating interplanetary magnetic field, you can have substorms going off once per hour.
"Heejeong used detailed statistical analysis to prove this phenomenon is real. Convection in the magnetosphere and ionosphere can be strongly driven by these fluctuations, independent of the direction of the interplanetary magnetic field."
Convection describes the transfer of heat, or thermal energy, from one location to another through the movement of fluids such as liquids, gases or slow-flowing solids.
"The energy of the particles and the fields in the magnetosphere can vary by large amounts. It can be 10 times higher or 10 times lower from day to day, even from half-hour to half-hour. These are huge variations in particle intensities, magnetic field strength and electric field strength," Lyons said.
The magnetosphere was discovered in 1957. By the late 1960s, it had become accepted among scientists that the energy transfer rate was controlled predominantly by the interplanetary magnetic field.
Lyons and Kim were planning to study something unrelated when they made the discovery.
"We were looking to do something else, when we saw life is not the way we expected it to be," Lyons said. "The most exciting discoveries in science sometimes just drop in your lap. In our field, this finding is pretty earth-shaking. It's an entire new mode of energy transfer, which is step one. The next step is to understand how it works. It must be a completely different process."
The National Science Foundation has funded ground-based radars which send off radio waves that reflect off the ionosphere, allowing scientists to measure the speed at which the ions in the ionosphere are moving.
The radar stations are based in Greenland and Alaska. The NSF recently built the Poker Flat Research Range north of Fairbanks.
"The National Science Foundation's radars have enabled us to make this discovery," Lyons said. "We could not have done this without them."
The direction of the interplanetary magnetic field is important, Lyons said. Is it going in the same direction as the magnetic field going through the Earth? Does the interplanetary magnetic field connect with the Earth's magnetic field?
"We thought there could not be strong convection and that the energy necessary for a substorm could not develop unless the interplanetary magnetic field is southward," Lyons said. "I've said it and taught it. Now I have to say, 'But when you have these fluctuations, which is not a rare occurrence, you can have substorms going off once an hour.'"
Lyons and Kim used the radar measurements to study the strength of the interaction between the solar wind and the Earth's magnetosphere.
One of their papers addresses convection and its affect on substorms to show it is a global phenomenon.
"When the interplanetary magnetic field is pointing northward, there is not much happening, but when the interplanetary magnetic field is southward, the flow speeds in the polar regions of the ionosphere are strong. You see much stronger convection. That is what we expect," Lyons said. "We looked carefully at the data, and said, 'Wait a minute! There are times when the field is northward and there are strong flows in the dayside polar ionosphere.'"
The dayside has the most direct contact with the solar wind.
"It's not supposed to happen that way," Lyons said. "We want to understand why that is."
"Heejeong separated the data into when the solar wind was fluctuating a lot and when it was fluctuating a little," he added. "When the interplanetary magnetic field fluctuations are low, she saw the pattern everyone knows, but when she analyzed the pattern when the interplanetary magnetic field was fluctuating strongly, that pattern completely disappeared. Instead, the strength of the flows depended on the strength of the fluctuations.
"So rather than the picture of the connection between the magnetic field of the sun and the Earth controlling the transfer of energy by the solar wind to the Earth's magnetosphere, something else is happening that is equally interesting. The next question is discovering what that is. We have some ideas of what that may be, which we will test."
University of California - Los Angeles
Charged particles carry currents, which cause significant modifications in the Earth's magnetosphere. This region is where communications spacecraft operate and where the energy releases in space known as substorms wreak havoc on satellites, power grids and communications systems.
The rate at which the solar wind transfers energy to the magnetosphere can vary widely, but what determines the rate of energy transfer is unclear.
"We thought it was known, but we came up with a major surprise," said Lyons, who conducted the research with Heejeong Kim, an assistant researcher in the UCLA Department of Atmospheric and Oceanic Sciences, and other colleagues.
"This is where everything gets started," Lyons said. "Any important variations in the magnetosphere occur because there is a transfer of energy from the solar wind to the particles in the magnetosphere. The first critical step is to understand how the energy gets transferred from the solar wind to the magnetosphere."
The interplanetary magnetic field fluctuates greatly in magnitude and direction.
"We all have thought for our entire careers - I learned it as a graduate student - that this energy transfer rate is primarily controlled by the direction of the interplanetary magnetic field," Lyons said. "The closer to southward-pointing the magnetic field is, the stronger the energy transfer rate is, and the stronger the magnetic field is in that direction. If it is both southward and big, the energy transfer rate is even bigger."
However, Lyons, Kim and their colleagues analyzed radar data that measure the strength of the interaction by measuring flows in the ionosphere, the part of Earth's upper atmosphere ionized by solar radiation. The results surprised them.
"Any space physicist, including me, would have said a year ago there could not be substorms when the interplanetary magnetic field was staying northward, but that's wrong," Lyons said. "Generally, it's correct, but when you have a fluctuating interplanetary magnetic field, you can have substorms going off once per hour.
"Heejeong used detailed statistical analysis to prove this phenomenon is real. Convection in the magnetosphere and ionosphere can be strongly driven by these fluctuations, independent of the direction of the interplanetary magnetic field."
Convection describes the transfer of heat, or thermal energy, from one location to another through the movement of fluids such as liquids, gases or slow-flowing solids.
"The energy of the particles and the fields in the magnetosphere can vary by large amounts. It can be 10 times higher or 10 times lower from day to day, even from half-hour to half-hour. These are huge variations in particle intensities, magnetic field strength and electric field strength," Lyons said.
The magnetosphere was discovered in 1957. By the late 1960s, it had become accepted among scientists that the energy transfer rate was controlled predominantly by the interplanetary magnetic field.
Lyons and Kim were planning to study something unrelated when they made the discovery.
"We were looking to do something else, when we saw life is not the way we expected it to be," Lyons said. "The most exciting discoveries in science sometimes just drop in your lap. In our field, this finding is pretty earth-shaking. It's an entire new mode of energy transfer, which is step one. The next step is to understand how it works. It must be a completely different process."
The National Science Foundation has funded ground-based radars which send off radio waves that reflect off the ionosphere, allowing scientists to measure the speed at which the ions in the ionosphere are moving.
The radar stations are based in Greenland and Alaska. The NSF recently built the Poker Flat Research Range north of Fairbanks.
"The National Science Foundation's radars have enabled us to make this discovery," Lyons said. "We could not have done this without them."
The direction of the interplanetary magnetic field is important, Lyons said. Is it going in the same direction as the magnetic field going through the Earth? Does the interplanetary magnetic field connect with the Earth's magnetic field?
"We thought there could not be strong convection and that the energy necessary for a substorm could not develop unless the interplanetary magnetic field is southward," Lyons said. "I've said it and taught it. Now I have to say, 'But when you have these fluctuations, which is not a rare occurrence, you can have substorms going off once an hour.'"
Lyons and Kim used the radar measurements to study the strength of the interaction between the solar wind and the Earth's magnetosphere.
One of their papers addresses convection and its affect on substorms to show it is a global phenomenon.
"When the interplanetary magnetic field is pointing northward, there is not much happening, but when the interplanetary magnetic field is southward, the flow speeds in the polar regions of the ionosphere are strong. You see much stronger convection. That is what we expect," Lyons said. "We looked carefully at the data, and said, 'Wait a minute! There are times when the field is northward and there are strong flows in the dayside polar ionosphere.'"
The dayside has the most direct contact with the solar wind.
"It's not supposed to happen that way," Lyons said. "We want to understand why that is."
"Heejeong separated the data into when the solar wind was fluctuating a lot and when it was fluctuating a little," he added. "When the interplanetary magnetic field fluctuations are low, she saw the pattern everyone knows, but when she analyzed the pattern when the interplanetary magnetic field was fluctuating strongly, that pattern completely disappeared. Instead, the strength of the flows depended on the strength of the fluctuations.
"So rather than the picture of the connection between the magnetic field of the sun and the Earth controlling the transfer of energy by the solar wind to the Earth's magnetosphere, something else is happening that is equally interesting. The next question is discovering what that is. We have some ideas of what that may be, which we will test."
University of California - Los Angeles
Magnetic Field Current Events and Magnetic Field News RSSNew study confirms exotic electric properties of graphene
First, it was the soccer-ball-shaped molecules dubbed buckyballs. Then it was the cylindrically shaped nanotubes. Now, the hottest new material in physics and nanotechnology is graphene: a remarkably flat molecule made of carbon atoms arranged in hexagonal rings much like molecular chicken wire.
New explanation for nature's hardiest life form
Got food poisoning? The cause might be bacterial spores, en extremely hardy survival form of bacteria, a nightmare for health care and the food industry and an enigma for scientists.
A bubbling ball of gas
The Sun is a bubbling mass. Packages of gas rise and sink, lending the sun its grainy surface structure, its granulation. Dark spots appear and disappear, clouds of matter dart up - and behind the whole thing are the magnetic fields, the engines of it all.
German high-school students involved in an astronomical research project
This week, Astronomy & Astrophysics publishes a somewhat unusual research article because it is co-authored by German high-school students.
New TMS clinic offers noninvasive treatment for major depression
Rush University Medical Center has opened the Transcranial Magnetic Stimulation (TMS) Clinic to offer patients suffering from major depression a safe, effective, non-drug treatment.
Carbon atmosphere discovered on neutron star
Evidence for a thin veil of carbon has been found on the neutron star in the Cassiopeia A supernova remnant. This discovery, made with NASA's Chandra X-ray Observatory, resolves a ten-year mystery surrounding this object.
High-performance plasmas may make reliable, efficient fusion power a reality
In the quest to produce nuclear fusion energy, researchers from the DIII-D National Fusion Facility have recently confirmed long-standing theoretical predictions that performance, efficiency and reliability are simultaneously obtained in tokamaks, the leading magnetic confinement fusion device, operating at their performance limits.
A special issue on the International Workshop of the 2008 Solar Total Eclipse
On August 1, 2008 a total solar eclipse was visible within a narrow corridor that traversed from North America to China.
Magnetic mixing creates quite a stir
Sandia researchers have developed a process that can mix tiny volumes of liquid, even in complicated spaces.
NIST physicists turn to radio dial for finer atomic matchmaking
Investigating mysterious data in ultracold gases of rubidium atoms, scientists at the Joint Quantum Institute of the National Institute of Standards and Technology (NIST) and the University of Maryland and their collaborators have found that properly tuned radio-frequency waves can influence how much the atoms attract or repel one another, opening up new ways to control their interactions.
More Magnetic Field Current Events and Magnetic Field News Articles
 |
Distortion by Magnetic Fields Distortion, Magnetic Fields’ second Nonesuch release, features the brilliant melodies and wry lyrics that composer and band leader Stephin Merritt has long been praised for, but, as the album title suggests, he serves them up with a twist. If the late, great Cole Porter had somehow been resurrected just in time to appear at the Coachella indie-rock fest, the results might sound something like this –"small, ironic tales of love and woe," as National Public Radio has described Merritt’s songs, startlingly enveloped in layers of live feedback that recall the noisy pop provocations of legendary Scottish quartet The Jesus and Mary Chain. As album producer, Merritt takes a completely novel approach to his deployment of feedback, going well beyond mere fuzzed-out guitar to... |
 |
69 Love Songs by Magnetic Fields 1999 and first new material in four years by Stephin Merrit 's main band (his side projects include Future Bible Heroes, Gothic Archies and The 6ths). Limited three disc set f eaturing more wonderful, yet cynically skewed, pop songs as only Merritt (and a midi) can do 'em! Features all three volumes of '69 Love Songs' (also sold separately), as well as a76 page booklet only available in this box! Each disc comes in a separate standard jewel case & together they come in a colorful CD-sized slipcase box. 69 tracks. |
 |
69 Love Songs by The Magnetic Fields Re-mastered limited edition (3,000) deluxe vinyl re-issue of their classic 1999 3-CD box set rumination on love. Funny, smart, dark, and memorable. Stephin Merritt solidifies his songwriting genius on his "most ambitious and fully realized work" - AMG. Beautifully packaged in a 10-inch slip case box with three double gatefold sleeves and the original booklet in 10-inch size. Includes coupon for MP3 download of entire album. |
 |
i by Magnetic Fields The long-awaited follow-up to the acclaimed 1999 release 69 Love Songs, i finds singer/songwriter Stephin Merritt in full possession of his acerbic wit. Featuring lyrics ripe with melancholy and bittersweet imagery, the record's fourteen tracks are possibly the most personal Merritt has created to date -- a departure from the many voices on 69 Love Songs. |
 |
The Charm of the Highway Strip by Magnetic Fields Sweet and sour, incurably romantic, and deeply misanthropic, Magnetic Fields' mastermind Stephin Merritt is a one-of-a-kind voice in modern lo-fi pop. This 1994 outing is a bit of a departure, with Merritt taking his trademark ABBA-styled Casio-pop for a spin in the country--literally. Awash in lush, Nashville-ready production, songs like the doleful "Lonely Highway" (which encompasses snatches of the Lee Hazelwood classic "Jackson") and "Born on a Train" are nothing short of thrilling. But much of this particular stretch of the Fields is lacking in charm, since Merritt's wry stance chafes a bit too hard against the guileless melodies. Completists may feel compelled to take a ride, but novices should probably stick to the more urbane journeys offered by Holiday and Distant Plastic Trees.... |
 |
Magnetic Field(s) by Ron Loewinsohn (Author) Organised around the idea that "you can't know what a magnetic field is like unless you're inside of it," Ron Loewinsohn's first novel opens from the disturbing perspective of a burglar in the midst of a robbery, and travels through the thoughts and experiences (both real and imaginary) of a group of characters whose lives are connected both coincidentally and intimately. All of the characters have a common desire to imagine and invent rather horrifying stories about the lives of people around them. As the novel develops, certain phrasings and images recur improbably, drawing the reader into a subtle linguistic game that calls into question the nature of authorship, the ways we inhabit and invade each other's lives, and the shape of fiction itself. |
 |
Get Lost by Magnetic Fields |
 |
The Wayward Bus/Distant Plastic Trees by Magnetic Fields |
 |
69 Love Songs Volume 1 The Magnetic Fields (Primary Contributor) |
 |
69 Love Songs, Pt. 1 by Magnetic Fields 1999 and first new material in four years by Stephin Merrit 's main band (his side projects include Future Bible Heroes, Gothic Archies and The 6ths). Disc one of a three CD set featuring more wonderful, yet cynically skewed, pop songs as only Merritt (and a midi) can do 'em! 23 tracks. |
| © 2009 BrightSurf.com |