MagnetosphereIonosphere coupling processes reflected in

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Magnetosphere-Ionosphere coupling processes
reflected in Cluster II and EISCAT data
Outflow of ionospheric ions
Wenlong Liu, Rashmi Rawat, Rong Liu, Liu Yuan Li,
Guo Xiaocheng, Tarun Kumar Pant
Project Tutor Prof. Stephan Buchert
Regional Workshop for Space Physicists from
South-East Asia

13th May
2004
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Presence of O ions has been shown at near and
far magnetosphere through satellite observations
in the nightside !!
Where do ionospheric O go?? -ring current? -ps
boundary layer? -central plasma
sheet? -downstream solar wind? Do they play a
role for magnetospheric plasma processes such as
magnetic reconnection??
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Polar Cusp
Ion outflow
Eambipolar
Electron heating
Ambipolar Diffusion 300km
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Auroral region
Upward accelerated ions
Heightgt1000 km
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Injection of O into the Magnetosphere
Nightside
Dayside
Gazey et al. 1996
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Dayside ambipolar outflow has low energy (eV)
Mechanisms for further energisation are
unclear! Dayside outflow is relatively
persistent and can reach high flux.
Auroral outflow accelerates efficiently to keV
energies above gt 1000km Occurs only during
substorm activity It can not be seen directly
with EISCAT radar.
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One should have simultaneous measurements in
polar cusp, auroral ionosphere and magnetosphere!
Present Study and the measurements used
a. EISCAT radar data from day side b. Cluster II
data from the tail (c. Polar Satellite -TIM data)
Geomagnetic indices
Period August October 2002
Two representative events have been found and are
being presented
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Case 1 23rd Aug 2002
High electron temperature
Up flow of O
11 MLT
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Lobe
Sheet
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Enhanced density ratio 60 in bl
No O in cps
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AE index shows very low activity
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Case-I 23rd August 2002 , quiet day
a. A strong ionospheric outflow of O from the
cusp is seen with EISCAT b. Cluster CIS detects
enhanced O of few keV in the plasma sheet
boundary layer How is O accelerated ?? c. No
major substorm activity seen d. No O in the
central plasma sheet In this case O is unable
to reach ring current/inner magnetosphere?? Prov
e that boundary layer plasma is from open
field-lines?
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7th Oct. 2002
Electron heating
Weak upflow
10 MLT
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Energetic O in plasma sheet
Due to plasma sheet motion
Low energy population in bl
O enhancement
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Enhanced ratio only in ps
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AE index shows significant activity near 8 UT
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Case-II 7th October 2002 Disturbed day
a. O in boundary layer at low energy 100
eV Probably due to the dayside outflow (similar
to Case-I) b. Significant O in the central
plasma sheet time of flight effect ?? Probably
due to auroral, substorm related outflow
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Goals for the future work
a. More quatitative modeling by combining field
line tracing and convection model. Forward
tracing of EISCAT events Backward tracing of
Cluster events b. More quantitative estimation
of the frequency and flux of outflow from the
dayside. c. Investigation of the variation of
density and flux of O ions in different
magnetospheric regions like the boundary layer,
central plasma sheet and ring current
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Required data resources 1. EISCAT radar for
ionospheric outflow flux and
velocity in the high
latitude region
2. Cluster satellite in the magnetotail
and plasma
sheet region
3. IMAGE, POLAR, DMSP, AKEBONO, TC-2
Event selection and preliminary investigations
December 2004 Required Modeling resources
Magnetic field models like Tsyganenko
models and
electric field models for tracing
the ion
trajectories. Model comparisons
April 2005
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Task Assignment
Satellite data analysis Wenlong Liu, Rashmi
Rawat, Tarun Pant Modelling and comparisons
Rong Liu, Liu Yuan Li, Guo Xiaocheng
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Thanks !!!!