Los Alamos Magnetospheric Plasma Analyzer MPA

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Los AlamosMagnetospheric Plasma Analyzer(MPA)

• LASSO Summer 2007 Workshop
• July 2007

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Why is LANL in space?
NUDET Detection Verification Defense
support Nonproliferation Remote sensing Space
Weather Monitoring Basic Research High-energy
astrophysics RF physics (esp. lightning) Solar
wind physics Magnetospheric physics Planetary
physics Ionospheric/atmospheric physics
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History of space environment programs at LANL

• DOE/Defense
• Vela
• Past geosynch
• GPS/DSP
• Current geosynch
• SABRS/SAVE

• Basic Research
• IMP
• ISEE
• Ulysses
• Polar
• FAST
• Cassini
• ACE
• Deep Space-1
• Lunar Prospector
• Cluster
• Genesis
• IMAGE
• TWINS
• Mars 2001
• Messenger
• DAWN
• IBEX
• RBSP

• Competencies
• Space-borne instrumentation
• Sensor science
• Data handling
• Solar wind science
• Magnetospheric science
• Planetary science
• RF physics

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Geosynchronous Orbit
T (4p2/GM)1/2 r3/2
T 24 hours for r 6.6 RE
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Geosynchronous OrbitThe Crossroads of the
Magnetosphere
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LANL Geosynchronous Satellites

• Currently 7 satellites
• Energetic particle and plasma detectors
• Full velocity-space coverage, ions and electrons
• e- 1 eV - 26 MeV
• i 1 eV - gt20 MeV
• Background characterization/discrimination
• Spacecraft anomaly support
• ? Near-real-time delivery to Air Force, NOAA, and
  NASA
• Long-term environment specification
• ? Long-term surface-charging and killer
  electron" studies
• ? Basic understanding of space weather phenomena

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Geosynchronous Satellite Locationsat 0 UT on 18
September 2002
LANL-97A
LANL-02A
1994-084
YGSE (RE)
LANL-01A
1991-080
1990-095
(1989-046)
XGSE (RE)
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Magnetospheric Plasma Analyzer
Mass 3.6 kg Power 3.5 watt
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MPA Measurement Objective
Measure the magnetospheric plasma environment in
the neighborhood of the spacecraft.
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Describing a Gas
v
Each particle is characterized by its speed and
its direction of motion, i.e., its vector
velocity, v Full description Number of
particles within a given volume of space ?x that
are moving with velocities in a range ?v about v
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Plasma Distributions
fe(x,v) fi1(x,v) fi2(x,v)
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Particle Distributions
Measurement questions How fast and in what
direction is each particle going? How many are
there?
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MPA Measurement Principle
Counter
Detector
Electrostatic Analyzer
Entrance
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Electrostatic Energy Analyzer
transmitted particle energy too small energy too
large wrong charge sign
E
incident particle
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DetectorChannel Electron Multiplier(CEM)
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Each CEM views a different direction in space
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Los Alamos National LaboratoryMagnetospheric
Plasma Analyzer (MPA)
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Energy-Time Spectrogram(ions)
Color-coded count rate -gt distribution function
looking east
log energy (eV) -gt
looking west
time -gt
Cold, dense, anisotropic
Indicator of surface charging
Penetrating background
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Ions and electrons have very different energy
distributions
Ions
log energy (eV) -gt
Electrons
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Derived Parameters
Example Densities
18 LT
LANL-02A
2 July 2003
UT
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Some MPA Results
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Some MPA Results
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Introduction to theMPA Data Analysis Project
Cold, Dense Plasma at Geosynchronous Orbit
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From the LANL MPA Website(http//mpa.lanl.gov/cgi
-bin/search.cgi)
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Energy-Time Spectrograms(Satellite LANL-02A)
log energy (eV) -gt
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Local TimeLocal Time is not a time at all!It
refers to an orbital location.
7 LT
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3
9
12
0
15
21
18
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Local Time, Universal Time, and Longitude
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Interpretation of Results
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Plasma Circulation in the Magnetosphere(Equatoria
l View)
Corotation
Sunward Convection
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The PlasmasphereCold Plasma from the Ionosphere
Particle drift trajectories
Particles outside separatrix flow through and are
lost -gt short residence time.
Particles inside separatrix can circle the earth
many times -gt long residence time.
separatrix
With a long residence time, cold plasma coming up
from the ionosphere can build up to high
densities, producing the plasmasphere.
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The location of the separatrix depends on the
strength of the convection
Strong Convection (high Kp) Geosynchronous orbit
never enters the plasmasphere
Weak Convection (low Kp) Geosynchronous orbit
lies mostly inside the plasmasphere
13 June 1996
7 Nov 2001
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The location of the separatrix depends on the
strength of the convection
Strong Convection (high Kp) Geosynchronous orbit
never enters the plasmasphere
Weak Convection (low Kp) Geosynchronous orbit
lies mostly inside the plasmasphere
Increasing convection produces a drainage plume