Scientists "de-SCIFER" Physicsof the Earth's Plasma Fountain
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Scientists "de-SCIFER" Physics of the Earth's Plasma Fountain
Scientists "de-SCIFER" Physics of the Earth's Plasma Fountain
August 12, 1996: A
recent rocket flight carrying two Space Sciences Laboratory instruments
from the Marshall Space Flight Center has returned data that has offered
a better understanding of a portion of the Earth's magnetosphere. Much of
these data were recently published in a special issue of Geophysical Research
Letters (GRL), a science journal for timely, cutting edge research results
in geophysics. In all, seven different papers in the July 1 edition of GRL
describe the initial results from the SCIFER
rocket, which flew in January 1995.
SCIFER, which stands for Sounding of the Cleft Ion Fountain Energization
Region, carried two experiments from SSL designed to measure various plasma
components in a particular region of the Earth's magnetosphere. The Cleft
Ion Fountain is a plasma fountain that sprays plasma made from our atmosphere
up over the poles and feeds the plasma storm process on the night side of
the Earth. The SCIFER observations show that this region is richer in hydrogen
plasma and depleted of oxygen plasma relative to earlier MSFC observations
made from the Dynamics Explorer (DE)
satellite. Scientists have attributed this result to a difference between
high solar activity during the DE flight period and low solar activity during
the SCIFER flight.
SCIFER also shows that the fountain heating or "energization region",
has a very sharp boundary in the direction of the Earth's equator, only
about 1 km thick. Furthermore, plasma in the energization region displays
an inverse relationship between the density and temperature; where the temperature
is high, the density is low, and vice-versa. This behavior is seen in both
the electrons and the ions which make up the plasma. The physics involved
in the heating region are not completely understood, however these are significant
clues to the operative mechanisms of this heating.
A similar rocket payload named CAPER with two additional MSFC experiments
has been selected for launch in early 1998 to further explore this region
and better determine the mechanisms of heating.
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HeadlinesAuthors: John
Horack , Tom Moore
Curator: Bryan Walls
NASA Official: John M. Horack