Secret of Earth's magnetic shield unravelled - Magnetosphere is cracked!

clark · 2003-05-20 12:42:06

Secret of Earth's magnetic shield unravelled by US-European spacecraft

PARIS (AFP) May 20, 2003

American and European spacecraft have stumbled upon a secret of the magnetosphere, the magnetic field which shields the Earth from harmful particles blasted out by the Sun, the European Space Agency (ESA) said here Tuesday.
Scientists believe they can now explain an enigmatic phenomenon, "dayside proton auroral spots," in which bright ultra-violet spots show up in the atmosphere.
Data sent back by NASA's orbiting spacecraft Image and ESA's four Cluster spacecraft have now confirmed for the first time that the phenomenon occurs thanks to cracks that briefly open up in the Earth's magnetic field, it said in a press statement.
The so-called solar wind spewed out by the Sun comprises a constant bombardment of hydrogen atoms, whose constituent pieces are protons and electrons, and from which we are shielded by the magnetosphere.
When hydrogen electrons enter our atmosphere, they collide with and excite the atoms in the air, and the energy is transformed into light, creating the aurora "curtains" familiar to people who live in extreme latitudes.
The auroral spots are different, though: they occur when protons "steal" electrons from atmospheric molecules, and the energy is released in a shining blob of light.
The breakthrough occurred on March 18 last year, when sensors aboard Image detected a bright "spot" that was generated as a jet of solar protons wacked into the atmosphere, ESA said.
By great good luck, the Cluster spacecraft were passing overhead at that very moment, making a routine sweep of the Earth's magnetic field.
"An extensive analysis of the Cluster results has now shown that the region was experiencing a turbulent event known as 'magnetic reconnection'," ESA said.
"Such a phenomenon takes place when the Earth's usually impenetrable magnetic field fractures and has to find a new stable configuration.
"Until the field mends itself, solar protons leak through the gap and jet into Earth's atmosphere creating the dayside proton aurora."
The discovery will be published this week in a specialist journal, Geophysical Research Letters, ESA added.

Josh Cryer · 2003-05-20 14:36:28

Why does it fracture in the first place? In my opinion, this is only telling us half the picture.

clark · 2003-05-20 14:48:04

link: Magnetic Reconnection link

What is magnetic reconnection?

Magnetic reconnection (henceforth called "reconnection") refers to the breaking and reconnecting of oppositely directed magnetic field lines in a plasma. In the process, magnetic field energy is converted to plasma kinetic and thermal energy.
Reconnection is at the heart of many spectacular events in our solar system. For example, solar flares which occur near sunspots are believed to be powered by magnetic reconnection. Solar magnetic activity, including flares, can eject high energy charged particles into space. When the particles reach Earth, they can disrupt power grids and communications systems and threaten spacecraft and satellites. A related phenomenon is the aurora seen near the polar regions of Earth as well as on other magnetized planets. The Earth's own magnetic field is constantly perturbed by the impinging field from the sun (called the solar wind). During strong bursts (such as those caused by extraordinary solar flares) reconnection can be induced in the near-Earth magnetotail (a narrow magnetic field structure located on the night side many Earth-radii away). The tenuous plasma in that region is then accelerated down magnetic field lines into the polar regions, striking Earth's atmosphere and exciting nitrogen and oxygen atoms as well as other atoms present in our atmosphere. The immediate de-excitation of these atoms then emit the wonderful and often intricate display of light we know as the aurora or northern (and southern) lights.
In plasma physics, it is well known that magnetic field lines are "frozen-in" to an infinitely conductive plasma. Since charged plasma particles are confined to circular orbits around magnetic field lines, this means that infinitely conductive plasmas will not diffuse across field lines and mix. Conversely, two distinct field lines will remain separate since they cannot penetrate the intervening plasma. In most cases, solar and magnetospheric plasmas can be described very accurately with such a theory since they are both very conductive. However, straightforward application of the theory would remove the possibility of ejected solar plasma penetrating the magnetosphere since the plasmas would not be allowed to mix. Nevertheless, based on observations and known technological disruptions, we know that they must mix, but how?
The answer resides in the fact that when plasmas carrying oppositely directed magnetic field lines are brought together, a strong current sheet is established, in the presence of which even a vanishingly small amount of resistivity in a small volume can become important, allowing plasma diffusion and, thus, magnetic reconnection to occur.

There is a basic picture detailing the flow interaction on the website linked to.

SpaceNut · 2020-12-09 21:10:15

Sun spots and solar storms are not new but every now and again they reek havic on the satelites on orbit and electrical stations on the ground.
Sun launches explosion of electromagnetic energy towards Earth: Geomagnetic Storm Watch issued

You may be able to see the effects of this storm
hypatia-h-8c776c0b6885ebe0e428fce572c8e3e6-h-39c755f927d6b7b962f447919fbb8302-1607562946.jpg?resize=660:*

SpaceNut · 2020-12-10 21:00:02

New sunspot cycle could be one of the strongest on record, new research predicts

Sun has overlapping 22-year magnetic cycles that interact to produce the well-known, approximately 11-year sunspot cycle as a byproduct. The 22-year cycles repeat like clockwork and could be a key to finally making accurate predictions of the timing and nature of sunspot cycles, as well as many of the effects they produce, according to the study's authors.

Mars_B4_Moon · 2022-03-12 05:38:12

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2022 Mar 12 0259 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

https://www.swpc.noaa.gov/products/aler … d-warnings

Solar storm warning as huge eruption from Sun to deliver 'glancing blow' to Earth in hours

https://www.express.co.uk/news/science/ … ce-weather

SpaceNut · 2022-03-12 10:28:39

This relates to the radiation shield envisioned for the Large ships ability to survive.
emission of event at the suns surface time and date was
ALERT: Geomagnetic K-index of 4
Threshold Reached: 2022 Feb 10 1625 UTC
Synoptic Period: 1500-1800 UTC

current alert Issue Time: 2022 Mar 12 0302 UTC

so days ago we knew it was coming.

New Mars Forums

Announcement

#1 2003-05-20 12:42:06

Re: Secret of Earth's magnetic shield unravelled - Magnetosphere is cracked!

#2 2003-05-20 14:36:28

Re: Secret of Earth's magnetic shield unravelled - Magnetosphere is cracked!

#3 2003-05-20 14:48:04

Re: Secret of Earth's magnetic shield unravelled - Magnetosphere is cracked!

#4 2020-12-09 21:10:15

Re: Secret of Earth's magnetic shield unravelled - Magnetosphere is cracked!

#5 2020-12-10 21:00:02

Re: Secret of Earth's magnetic shield unravelled - Magnetosphere is cracked!

#6 2022-03-12 05:38:12

Re: Secret of Earth's magnetic shield unravelled - Magnetosphere is cracked!

#7 2022-03-12 10:28:39

Re: Secret of Earth's magnetic shield unravelled - Magnetosphere is cracked!

Board footer