The mesmerizing aurora, with its vibrant green, red and purple curtains, has long captivated night sky watchers. However, the recent appearance of strange aurora-like phenomena – the violet-white streaks known as “Steve” and their often accompanying… Glowing green “Picket Fence” – has sparked the interest of scientists and sky watchers alike.
First identified in 2018 as a variant of the more famous aurora, Steve, named after a character in a 2006 children’s film, the picket fence phenomenon was initially thought to be a product of the same physical processes as aurora. However, this assumption left many questions unanswered about its unique origins Incandescent emissions.
A new mechanism generates sky flares
Enter Claire Gaskey, a promising graduate student in physics at the University of University of California, Berkeley. Gaske has proposed an interesting explanation for these phenomena, proposing a physical mechanism quite different from that responsible for conventional auroras.
“This would upend our model of what creates the light and energy in the aurora in some cases,” Gaskey said. “It’s really cool, and it’s one of the biggest mysteries in space physics right now.”
In cooperation with the Space Sciences Laboratory (SSL) At Berkeley, Gaske calls for a NASA A mission to launch a rocket at the aurora borealis to validate its hypothesis. This research coincides with the Sun entering a more active phase of its 11-year cycle, making this an opportune moment to study rare events like Steve and the picket fence.
Distinguishing “Steve” from the common aurora
Gaskey’s research focuses on the strange behavior of electric fields in the upper atmosphere. It suggests that these fields, parallel to the Earth’s magnetic field, may produce the spectrum of colors observed in the picket fence phenomenon.
This hypothesis challenges current models of auroral light and energy generation and has important implications for our understanding of the interaction between the Earth’s magnetosphere and the ionosphere.
Common aurorae are caused by solar wind energizing particles in the Earth’s magnetosphere, causing oxygen and nitrogen molecules in the upper atmosphere to emit specific frequencies of light.
However, STEVE shows a wide range of frequencies centered around magenta or violet, without the blue light typical of the more energetic particle interactions in the aurora. Interestingly, Steve and the picket fence occur at lower latitudes than the typical aurora, perhaps even near the equator.
Parallel electric fields are at play
Gaskey’s research posits that emissions from the “picket fence” are generated by electric fields at low altitudes parallel to the Earth’s magnetic field. Using a widely accepted physical model of the ionosphere, she demonstrated that a parallel electric field of about 100 millivolts per meter at an altitude of about 110 km can accelerate electrons.
This acceleration is sufficient to activate the oxygen and nitrogen atoms, leading to the emission of gas Light spectrum Observed in “Picket Fence” and “Steve’s” afterglow. It also identified unique conditions in this region, such as low plasma density and increased presence of neutral oxygen and nitrogen atoms. These can act as an insulator, preventing the electric field from causing a short circuit.
“If you look at the range of the picket fence, it’s a lot greener than you would expect. There’s no blue color that comes from nitrogen ionization,” Gaskey said. “What this tells us is that there is only a specific energy range of electrons that can create those colors.” “It can’t come from space into the atmosphere, because those particles have too much energy.”
Instead, she said, “The light emitted by the picket fence is generated by particles that must be energized out there in space by a parallel electric field, a mechanism very different from any of the aurora we have studied or known.” before.”
Search for Steve with missiles
Brian Hardingan assistant research physicist at SSL and co-author of Gaskey’s paper, highlights the importance of this discovery.
“The really interesting thing about Clare’s paper is that we’ve known for a couple of years that Steve’s spectrum tells us there’s some very strange physics going on. We didn’t know what it was,” Brian said. “Clare’s research showed that parallel electric fields are able to explain this strange spectrum.”
The team proposes launching rockets from Alaska to measure the electric and magnetic fields within these phenomena, with the aim of verifying the validity of their hypotheses. This endeavor is in line with NASA’s low-cost access to space (LCAS) It is expected to deepen our understanding of the chemistry and physics of the upper atmosphere. Initially, the target will be what is known as an enhanced aurora, which is a regular aurora containing “Steve” and “picket fence”-like emissions.
“The enhanced aurora is basically this bright layer included in the normal aurora. The colors are similar to the picket fence in that there’s not as much blue, there’s more green from oxygen and red from nitrogen. The hypothesis is that these also arise from “The path of parallel electric fields, but they are much more common than picket fences.”
The plan is not only to “fly a rocket through that enhanced layer to actually measure those parallel electric fields for the first time,” she said, but also to send a second rocket to measure molecules at higher altitudes, “to differentiate between conditions.” “One of the ones that cause aurora.” Eventually, she hopes to get a rocket that flies directly through Steve and the picket fence.
Curiosity drives this search for the aurora, Steve.
Gaskey attributes her success to collaboration with experts who study different layers of the atmosphere, including the mesosphere and stratosphere. This multidisciplinary approach has allowed significant progress in understanding the difference between the aurora and STEVE.
Harding, Gaske and their colleagues have submitted a proposal to NASA to launch a rocket campaign this fall, anticipating a response on its selection in the first half of 2024. Gaske and Harding see the experiment as a crucial step toward understanding the chemistry and physics of the planet. The upper atmosphere, the ionosphere, and the Earth’s magnetosphere.
“It’s fair to say that there will be a lot of studies in the future about how those electric fields got there, what waves are or aren’t associated with them, and what that means for the larger energy transfer between Earth’s atmosphere and space,” Harding said. “We really don’t know. Clare’s paper is the first step in this understanding.
The team is eagerly awaiting NASA’s decision on their proposed rocket campaign, expected in the first half of 2024.
In short, the research led by Claire Gaske represents a pivotal advance in space physics. Gaskey highlighted the elusive nature of “Steve” and the “picket fence” as something other than the aurora borealis. As the solar cycle progresses, these results promise not only to unravel the mysteries of these phenomena, but also to enhance our broader understanding of the dynamic interaction between Earth and space.
More about the Northern Lights
The Aurora Borealis, commonly known as the Northern and Southern Lights, stands as a mesmerizing natural light show in Earth’s polar sky. It occurs due to the wonderful interaction between the Earth’s atmosphere and the solar wind.
As discussed in detail above, scientists believe that STEVE and the picket fence are caused by the same physical processes as the aurora. However, this belief left many unanswered questions about the origins of their unique glowing emissions.
Origin: sun connection
The Sun, a source of energy and particles, constantly emits solar winds, which are streams of charged particles. During their journey towards Earth, these particles encounter the Earth’s magnetic field, which plays a crucial role in the formation of the aurora.
When it reaches Earth, the solar wind is affected by its magnetic field. The Earth’s magnetic field, extending into space, acts as a shield and directs these particles towards the poles. Here, magnetic field lines guide these charged particles into the Earth’s upper atmosphere.
Displays Steve’s flag and the Northern Lights
The basic phenomenon of auroras occurs when these charged particles, especially electrons, collide with gases such as oxygen and nitrogen in the Earth’s atmosphere. This collision transfers energy to gas molecules, exciting them and causing them to emit light, which is the essence of auroral displays.
The specific colors of the aurora and STEVE, which range from green and red to blue and violet, depend on the type of gas involved and the height of these interactions.
Solar activity greatly affects the intensity and frequency of aurora borealis. During solar maximum, increased solar flares and coronal mass ejections result in more intense and frequent aurora. Conversely, solar minimum results in decreased auroral activity.
Cultural and historical importance
In addition to their visual splendor, auroras provide valuable insights into the dynamics of the Earth’s magnetosphere and its interaction with solar radiation. Studying the aurora contributes to our understanding of how Earth’s magnetic field protects us from harmful solar emissions.
The aurora borealis has held a special place in various cultures, inspiring myths and folklore. From being the shields of valkyries in Norse mythology to representing ancestral spirits in indigenous beliefs, the aurora borealis have been a source of wonder and inspiration throughout history.
In short, the aurora borealis, with its stunning beauty, is more than just a visual spectacle. It is a dynamic interaction between the solar wind and our planet’s magnetic field, providing insight into Earth’s protective shield and continuing to fascinate people across cultures and generations.
The full study is published in the journal Geophysical Research Letters.
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