As technology becomes more integrated into our everyday lives, it becomes increasingly important to understand space weather and how it impacts technology.
When you hear “space weather“One typically thinks of massive explosions on the Sun — coronal mass ejections that are thrown toward Earth and are formed in the process beautiful depictions of northern lights.
However, not all space weather begins at the sun.
The Volcano eruption in Tonga in January 2022 was so large that it created ripples in the upper atmosphere that were a form of space weather in their own right.
It was one of the largest blasts in modern history, affecting GPS across Australia and Southeast Asia. As we describe in our new study in the journal space weatherthe eruption created a super “plasma bubble” over northern Australia that lasted for hours.
A truly global positioning system
While most people have a GPS (Global Positioning System) receivers on their devices (e.g. navigation devices and smartphones), not many people know how GPS actually works.
Essentially, our devices listen to radio signals sent out by satellites orbiting the earth. Using these signals, they calculate their location relative to the satellites, allowing us to get our bearings and find the nearby pub or restaurant Coffee Business.
The radio signals received by our devices are influenced by the earth’s atmosphere (especially the so-called earth’s atmosphere). ionosphere), which affects location accuracy. Conventional devices are only accurate to several tens of meters.
However, new and improving precision satellite positioning systems used in mining, agriculture and construction can achieve an accuracy of up to ten centimetres. The only catch is that these systems take time to determine their location and this can take 30 minutes or more.
The precise satellite positioning works by accurately modeling the errors caused by the Earth’s ionosphere. But whenever the ionosphere is perturbed, it becomes complicated and difficult to model.
For example if a geomagnetic storm (a disturbance in the solar wind that affects the Earth’s magnetic field) occurs, the ionosphere becomes turbulent and radio waves traveling through it are scattered – like visible light diffracted and scattered when looking into a lake in choppy conditions.
A volcanic fault
Current Studies have shown that the eruption of the Hunga Tonga-Hunga Ha’apai volcano caused turbulent conditions in the ionosphere that lasted for a few days. The size of the waves it generated in the ionosphere were similar to those generated by it geomagnetic storms.
While these waves affected GPS data around the world for days after the eruption, their impact on positioning was rather limited compared to another type of disturbance in the ionosphere — a “super-plasma bubble” that formed in the wake of the eruption.
The ionosphere is a layer of the Earth’s atmosphere at altitudes of about 80-800 kilometers (50-500 miles). It consists of gas with many electrically charged particles, making it a “plasma“.
Equatorial plasma bubbles, in turn, are plasma disturbances in the ionosphere that occur naturally over low-latitude regions at night.
Such plasma bubbles occur regularly. They arise due to a phenomenon called “generalized Rayleigh-Taylor instability.” It’s similar to what happens when a heavy liquid sits on top of a less heavy liquid and clumps of this lighter liquid rise up into the heavy liquid in the form of “bubbles” (see video below).
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However, when there are disturbances in the ionosphere, the plasma is also controlled by magnetic and electric fields.
As they rise, bubbles of plasma form strangely shaped structures resembling cacti or inverted tree roots. Because of the Earth’s magnetic field, these structures fan out as the bubble grows over the equator.
The result is that higher-lying bubbles also reach higher latitudes. Typically, plasma bubbles reach a few hundred kilometers above the equator and reach latitudes between 15 and 20 degrees north and south.
A rare bubble over Australia
scientists discovered A Super Plasma Bubble over Southeast Asia shortly after the Tonga eruption. The size is estimated to be similar to that previously reported rare super bubbles.
The Earth’s magnetic field carried this disturbance south, where it persisted for a few hours over Townsville in north-eastern Australia.
So far, this is the most southerly plasma bubble ever observed over Australia. While very rare, such superbubbles are known to have occurred over northern Australia, but were not directly observed prior to this event.
The introduction of GPS stations across Northern Australia has only recently made this type of observation possible.
The waves from the volcanic eruption are believed to have disrupted upper-atmospheric winds, altered plasma flow in the ionosphere, and led to the formation of the super-plasma bubble.
Our study found that the bubble caused significant delays in the use of accurate GPS in northern Australia and south-east Asia. In some cases, GPS location acquisition took over five hours longer due to the plasma bubble.
Although we know a lot about the ionosphere, our ability to predict its perturbations is still limited. More GPS stations are not only beneficial for improving positioning and navigation, but also fill gaps in ionosphere monitoring.
The Tonga eruption was anything but a typical “space weather” event caused by the sun. But its impact on the upper atmosphere and GPS underscores the importance of understanding how the environment affects the technologies we depend on.
Brett CarterAssociate Professor, RMIT University; Rezy PradiptaSenior Research Scientist, Boston CollegeAnd Suelyn Choyprofessor
This article was republished by The conversation under a Creative Commons license. read this original article.
