LENA Movies
(Click on the images to start the movies)
This LENA movie shows that there was a localized response in
the ionosphere due to the compression of the magnetosphere by
a CME shock front. The ionosphere is disturbed over a
considerable range of latitude but a relatively small range of
local time. LENA neutral atom observations show a dramatic
increase in the oxygen count rate from the general direction
of the Earth. The increase occurs about 38 minutes after the
disturbance, at 0951, consistent with the travel time of 30
eV neutral oxygen from the ionosphere to the spacecraft.
This suggests that there is no time delay between the
ionospheric disturbance and the initiation of ion outflow
from the ionosphere. See Fuselier et al., Ion outflow
observed by IMAGE: Implications for source regions and
heating mechanisms, Geophysical Research Letters, 28,
1163-1166, 2001 for further information.
Neutrals created by charge-exchange of low energy ion outflow
from the ionosphere are imaged by the Low Energy Neutral Atom
(LENA) imager on the IMAGE spacecraft. This movie shows that
enhanced neutral fluxes are associated with changes in the
solar wind during an ion outflow event on June 24, 2000 and
indicate that changes in solar wind density are associated
with episodic bursts of ion outflow. See Moore et al.,
Low energy neutral atoms in the magnetosphere, Geophysical
Research Letters, 28, 1143-1146, 2001 for more information.
One of the first discoveries LENA made was that there are neutral
atoms in the solar wind flow. One way LENA sees these are as
flux increases from the direction of the Sun when the solar
wind flux increases and one reason is enhanced solar wind
charge exchange with the Earth's geocorona, the neutral
atoms surrounding the Earth. This movie shows a simulation of
the expected neutral hydrogen flux observed at LENA due to the
solar wind interaction with the Earth's atmosphere on March
31, 2001. The simulation uses results from the
BATSRUS
global MHD code developed at the University of Michigan
and run by the
Community Coordinated Modelling Center
at NASA's Goddard Space Flight Center. The
simulation spectrogram compares favorably with the LENA data
on this day. See Collier et al., Observations of neutral atoms
from the solar wind, Journal of Geophysical Research, 106,
24,893-24,906, 2001 for more information.
