Plasma loss mechanisms from Saturn's magnetosphere

Dec 04, 2013
Saturn. Photo: NASA

Since the first up-close observations of Saturn, made by the Pioneer 11 probe in 1979, a great deal has been learned about the dynamics of the gas giant's magnetosphere. In-depth observations made by the Cassini orbiter, which has been circling Saturn since 2004, have revealed fundamental differences between the behavior of Saturn's magnetosphere and that of the Earth's magnetosphere.

Earth's magnetospheric plasma is largely populated by ions captured from the , whereas Saturn's plasma comes predominantly from water vapor that spews from massive geysers on the southern end of its icy moon Enceladus. Ionized from Enceladus streams out at 12 to 250 kilograms (27 to 551 pounds) per second, yet observations show that the concentration of plasma in Saturn's magnetosphere is at a relatively steady level. This discrepancy has left researchers searching for potential plasma loss mechanisms. In a review, Thomsen highlights the progress made in recent years in understanding this question.

According to the author, the main force driving plasma from Saturn's magnetosphere derives from the planet's fast rotation, which takes just 10.7 hours and produces currents in the magnetosphere that drive the plasma outward. These currents do not produce a uniform outflow—observations have shown interlocking fingers of cold inner magnetospheric plasma flowing outward and hot outer magnetospheric plasma flowing inward to take its place. Once it reaches the outer magnetosphere, the author says, the plasma can be lost to the solar wind, either crossing through the magnetopause or being swept down the magnetotail.

Observations made using the Cassini orbiter have shown mass loss through magnetic reconnection in the magnetotail, but current estimates suggest that this mechanism is inadequate to remove all of the plasma emerging from the inner .

Explore further: US-India to collaborate on Mars exploration

More information: Saturn's Magnetospheric Dynamics, Geophysical Research Letters, DOI: 10.1002/2013GL057967 , 2013

add to favorites email to friend print save as pdf

Related Stories

'Tis the season—for plasma changes at Saturn

May 03, 2013

(Phys.org) —A University of Iowa undergraduate student has discovered that a process occurring in Saturn's magnetosphere is linked to the planet's seasons and changes with them, a finding that helps clarify ...

Enceladus leaves plasma bubbles in its wake

Apr 15, 2010

(PhysOrg.com) -- Observations of how Saturn’s moon Enceladus interacts with its environment show it leaves a complex pattern of ripples and bubbles in its wake. Sheila Kanani will be presenting the results ...

Mercury's magnetic field measured by MESSENGER orbiter

May 15, 2012

Researchers working with NASA's Mercury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER) spacecraft report the frequent detections of Kelvin-Helmholtz (KH) waves at the edge of the innermost ...

Earth's magnetosphere behaves like a sieve

Oct 24, 2012

ESA's quartet of satellites studying Earth's magnetosphere, Cluster, has discovered that our protective magnetic bubble lets the solar wind in under a wider range of conditions than previously believed.

Recommended for you

US-India to collaborate on Mars exploration

58 minutes ago

The United States and India, fresh from sending their own respective spacecraft into Mars' orbit earlier this month, on Tuesday agreed to cooperate on future exploration of the Red Planet.

Swift mission observes mega flares from a mini star

1 hour ago

On April 23, NASA's Swift satellite detected the strongest, hottest, and longest-lasting sequence of stellar flares ever seen from a nearby red dwarf star. The initial blast from this record-setting series ...

Sandblasting winds shift Mars' landscape

5 hours ago

High winds are a near-daily force on the surface of Mars, carving out a landscape of shifting dunes and posing a challenge to exploration, scientists said Tuesday.

PanSTARRS K1, the comet that keeps going

8 hours ago

Thank you K1 PanSTARRS for hanging in there! Some comets crumble and fade away. Others linger a few months and move on. But after looping across the night sky for more than a year, this one is nowhere near ...

User comments : 0