Archive for the ‘CME (Coronal Mass Ejections)’ Category

Oslo-physicists use 20 new satellites to forecast space weather

The northern lights interfere with radio communications, GPS navigation and satellite communications. Researchers are now going to launch 20 satellites containing world class instruments from the University of Oslo to find out why.

Satellites are becoming increasingly important in communications and navigation. This makes us more vulnerable to the northern lights, especially within offshore and aviation. In a worst case scenario an aircraft can lose contact with its surroundings. Oil tankers can struggle with precise navigation.

In order to more precisely predict when radio communications and navigation will fail, researchers require more information about what happens when violent solar winds hit the Earth and produce the northern lights.

The solar winds consist of charged particles and produce powerful turbulence in the ionosphere, which consists of plasma clouds with electrical particles at an altitude of 80 to 500 km. The turbulence interferes with radio signals. Sometimes they are reflected wrongly. On other occasions the signals are blocked altogether.

“In the northern regions GPS satellites lie low in the sky. This means the signals have to pass through the ionosphere. This reinforces the navigation problems,” says professor Jøran Moen of the Department of Physics at University of Oslo (UiO), Norway.

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Solar Eruptions Cause Sunquakes

April 2, 2012 1 comment

A study led by UCL’s Mullard Space Science Laboratory has shown for the first time that sunquakes can be produced during eruptions of magnetic field and charged particles, as the immense magnetic structure blasts off into the Solar System. The results will be presented by Dr Sergei Zharkov at the National Astronomy Meeting 2012 in Manchester on Friday 30th March 2012.

The first observation of a sunquake was reported by Kosovichev & Zharkova in the late 1990s. During the last decade it has become well established that explosions in the Sun’s atmosphere, known as solar flares, can create sunquakes through the impact of powerful beams of particles which travel into the Sun. This new study shows that eruptions of material known as coronal mass ejections are also able to produce sunquakes.

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Space Weather Warnings for Earth & Forecasts for Exoplanets

March 29, 2012 Leave a comment

The UK Met Office’s weather and climate model is being adapted to help understand space weather at Earth and the atmospheres of planets orbiting other stars. Two teams of scientists will present their work at the National Astronomy Meeting in Manchester.

The Met Office plans to expand its services to provide operational space weather forecasts for the UK. It is pooling skills with the UK’s space weather research community to extend its ‘Unified Model’ upwards to include the Earth’s thermosphere, a region about 90-600km above the Earth surface. The impact of space weather events is very commonly seen in this region.

“Space weather can affect the aviation and power industries, as well as a whole range of activities that rely on GPS timing and positioning, radio communication or satellite-based observations,” said the Met Office’s Dr David Jackson, who will present the project on Friday 30th March.

“To develop a more accurate and useful advanced-warning system for space weather, we need to develop a system of interconnected models that describe the whole domain – the conditions on the Sun, interplanetary space, the layers of the Earth’s atmosphere, all the way down to the Earth’s surface. The more accurate we can be in representing interactions between the lower atmosphere and thermosphere, the more we can enhance thermospheric forecasts, and thus improve space weather forecast products for users,” Jackson continued.

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Solar ‘Climate Change’ Could Cause Rougher Space Weather

March 29, 2012 1 comment

Recent research shows that the space age has coincided with a period of unusually high solar activity, called a grand maximum. Isotopes in ice sheets and tree rings tell us that this grand solar maximum is one of 24 during the last 9300 years and suggest the high levels of solar magnetic field seen over the space age will reduce in future. This decline will cause a reduction in sunspot numbers and explosive solar events, but those events that do take place could be more damaging. Graduate student Luke Barnard of the University of Reading will present new results on ‘solar climate change’ in his paper at the National Astronomy Meeting in Manchester.

The level of radiation in the space environment is of great interest to scientists and engineers as it poses various threats to man-made systems including damage to electronics on satellites. It can also be a health hazard to astronauts and to a lesser extent the crew of high-altitude aircraft.

The main sources of radiation are galactic cosmic rays (GCRs), which are a continuous flow of highly energetic particles from outside our solar system and solar energetic particles (SEPs), which are accelerated to high energies in short bursts by explosive events on the sun. The amount of radiation in the near-Earth environment from these two sources is partly controlled in a complicated way by the strength of the Sun’s magnetic field.

There are theoretical predictions supported by observational evidence that a decline in the average strength of the Sun’s magnetic field would lead to an increase in the amount of GCRs reaching near-Earth space. Furthermore there are predictions that, although a decline in solar activity would mean less frequent bursts of SEPs, the bursts that do occur would be larger and more harmful.

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Spacecraft Observe Impact of Powerful Solar Storm

March 28, 2012 Leave a comment

For the first time, instrumentation aboard two NASA missions operating from complementary vantage points watched as a powerful solar storm spewed a two million-mile-per-hour stream of charged particles and interacted with the invisible magnetic field surrounding Earth, according to a paper published today in the Journal of Geophysical Research.

The spacecraft, NASA’s Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) and Interstellar Boundary Explorer (IBEX), observed the impact from inside and outside the Earth’s magnetosphere, respectively. The energetic neutral atom (ENA) cameras aboard each spacecraft enabled global imaging of the magnetosphere, the invisible bubble that protects Earth from the majority of charged particles from the Sun, as it compressed in response to sharply faster solar wind.

The storm, observed April 5, 2010, also is thought to have caused an important communications satellite, Galaxy-15, to founder and drift, taking almost a year to return to its station.

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Modeling Extreme Space Weather

March 26, 2012 Leave a comment

Explosions on the sun regularly disrupt the magnetic envelope surrounding Earth, but that envelope, the magnetosphere, largely protects the surface of the planet itself from space weather – with one exception. As a rule, changes in magnetic fields cause electric currents and vice versa, so all that change in the magnetosphere causes electric currents to form on the ground. Called geomagnetically induced currents or GICs, such currents extend some 60 miles underground, electrifying any conductors – power grid lines, or oil pipes, for example – along the way.

A big enough electrical surge from a GIC can knock out the transformers in a power grid. Electric companies can protect the grid from such surges by shutting down or lowering the power load on the system, but this, of course, costs money so they also don’t wish to be overly cautious by reducing power output unless it is really necessary. New analysis by scientists at NASA’s Goddard Space Flight Center in Greenbelt, Md., published online in Space Weather on February 23, 2012, provides some basic guidelines to help model some of the largest, most damaging GICs.

Risk analysis and adequate risk protection both rely on numerous factors. Modeling an extreme, devastating GIC is a crucial part of that picture. Referred to as 100-year events, that is, events so extreme they only happen on average once every 100 years, such currents could cause significant damage to Earth’s power grids worldwide. But proper preparation and accurate space weather forecasting could mitigate intense damage, the same way that communities can evacuate or protect their homes if given enough advance warning of a hurricane.

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Storms From the Sun

March 12, 2012 Leave a comment

Space weather starts at the sun. It begins with an eruption such as a huge burst of light and radiation called a solar flare or a gigantic cloud of solar material called a coronal mass ejection (CME). But the effects of those eruptions happen at Earth, or at least near-Earth space. Scientists monitor several kinds of space “weather” events — geomagnetic storms, solar radiation storms, and radio blackouts – all caused by these immense explosions on the sun.

One of the most common forms of space weather, a geomagnetic storm refers to any time Earth’s magnetic environment, the magnetosphere, undergoes sudden and repeated change. This is a time when magnetic fields continually re-align and energy dances quickly from one area to another.

Geomagnetic storms occur when certain types of CMEs connect up with the outside of the magnetosphere for an extended period of time. The solar material in a CME travels with its own set of magnetic fields. If the fields point northward, they align with the magnetosphere’s own fields and the energy and particles simply slide around Earth, causing little change. But if the magnetic fields point southward, in the opposite direction of Earth’s fields, the effects can be dramatic. The sun’s magnetic fields peel back the outermost layers of Earth’s fields changing the whole shape of the magnetosphere. This is the initial phase of a geomagnetic storm.

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