Planets which generate magnetic-fields in their interiors ,such as Earth ,Mercury ,Jupiter and Saturn ,are surrounded by invisible magnetospheres.Their magnetic fields deflect the charged particles of the solar wind (electrons and protons)as they stream away from the sun.This deflection creates Magnetosphere - a protective "bubble" around the planet - which ends in an elongated magnetotail on the lee side of the magnetosphere.
Since Venus has no intrinsic magnetic field to act as a shield against incoming charged particles ,the solar wind sometimes interacts directly with the upper atmosphere, However Venus is partially protected by an induced magnetic field .
As on earth ,solar ultraviolet radiation removes electrons from the atoms and molecules in the upper atmosphere ,creating a region of electrically charged gas known as the Ionosphere .This ionised layer interacts with the solar wind and the magnetic field carried by the solar wind .
During the continuous battle with the solar wind ,this region of the upper atmosphere is able to slowdown and divert the flow of particles around the planet creating a magnetosphere ,shaped rather like a comets tail ,on the lee side of the planet .
Spacecraft observations over many decades have shown that magnetic reconnection occurs frequently in the magnetospheres of Earth ,Mercury ,Jupiter and Saturn.This process which converts magnetic energy into kinetic energy occurs when oppositely directed magnetic field lines break and reconnect. with each other .On earth the reconnection is responsible for magnetic storms and polar auroras- the so called the northern and southern lights .
Until now ,reconnection was not generally thought to occur on non-magnetised planets.However first evidence of magnetic reconnection in Venus magnetotail has been found .
ESA's Venus Express Spacecraft follows a near polar orbit which is ideal to observe the Solar Wind - Ionosphere - Magnetotail interaction .On 15th May 2006 ,Venus Express was crossing the Venusian Magnetotail when it observed a rotational magnetic field structure over a period of about 3 minutes .Calculations based on the duration of observation and the speed of the spacecraft it implied that the magnetic field was 3400 km across. The event was an evidence of a transient magnetic loop structure which is formed by magnetic reconnection in a planetary magnetotail.
Further studies of the magnetic field data from Venus Express revealed the signatures of many similar observations of energy exchange between the magnetic field and the plasma in the tail.
The data also shows that ,in many respect s,the magnetosphere of venus is a scaled down version of Earth's.
The reconnection splits the magnetotail causing most of the plasms in the tail to be ejected into space.The discovery that plasma is lost from the tail as aresult of magnetic reconnections provides a possible new mechanism for explaining how and why gasses are lost from Venus's Upper Atmosphere .This has implications for understanding how Venus lost its water after the planet began to experience a runaway green house effect.
Since Venus has no intrinsic magnetic field to act as a shield against incoming charged particles ,the solar wind sometimes interacts directly with the upper atmosphere, However Venus is partially protected by an induced magnetic field .
As on earth ,solar ultraviolet radiation removes electrons from the atoms and molecules in the upper atmosphere ,creating a region of electrically charged gas known as the Ionosphere .This ionised layer interacts with the solar wind and the magnetic field carried by the solar wind .
During the continuous battle with the solar wind ,this region of the upper atmosphere is able to slowdown and divert the flow of particles around the planet creating a magnetosphere ,shaped rather like a comets tail ,on the lee side of the planet .
Spacecraft observations over many decades have shown that magnetic reconnection occurs frequently in the magnetospheres of Earth ,Mercury ,Jupiter and Saturn.This process which converts magnetic energy into kinetic energy occurs when oppositely directed magnetic field lines break and reconnect. with each other .On earth the reconnection is responsible for magnetic storms and polar auroras- the so called the northern and southern lights .
Until now ,reconnection was not generally thought to occur on non-magnetised planets.However first evidence of magnetic reconnection in Venus magnetotail has been found .
ESA's Venus Express Spacecraft follows a near polar orbit which is ideal to observe the Solar Wind - Ionosphere - Magnetotail interaction .On 15th May 2006 ,Venus Express was crossing the Venusian Magnetotail when it observed a rotational magnetic field structure over a period of about 3 minutes .Calculations based on the duration of observation and the speed of the spacecraft it implied that the magnetic field was 3400 km across. The event was an evidence of a transient magnetic loop structure which is formed by magnetic reconnection in a planetary magnetotail.
Further studies of the magnetic field data from Venus Express revealed the signatures of many similar observations of energy exchange between the magnetic field and the plasma in the tail.
The data also shows that ,in many respect s,the magnetosphere of venus is a scaled down version of Earth's.
The reconnection splits the magnetotail causing most of the plasms in the tail to be ejected into space.The discovery that plasma is lost from the tail as aresult of magnetic reconnections provides a possible new mechanism for explaining how and why gasses are lost from Venus's Upper Atmosphere .This has implications for understanding how Venus lost its water after the planet began to experience a runaway green house effect.
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