Groundbased Magnetometer Array for the IHY

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Ground-based Magnetometer Array for the IHY

• Dr. Ian R. Mann
• CANOPUS PI.
• Canada Research Chair in Space Physics
• Dept. of Physics, University of Alberta.
• E-mail imann_at_space.ualberta.ca

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IHY Magnetometer Array

• Magnetometer Arrays provide a relatively low-cost
  method for monitoring the solar-terrestrial
  interaction.
• Magnetometer stations provide monitoring of
  current systems local to monitoring station, as
  well as local wave populations.
• Multi-continental IHY array would provide
  excellent basis for global monitoring of space
  weather disturbances.
• Excellent scientific targets for mid- and
  low-latitudes perfect match for potential
  locations of the developing nations who may
  participate.

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Potential Science Targets

• The IHY magnetometer array would provide
  capability for global monitoring of magnetic
  disturbances and current systems in developing
  countries at mid- and low- magnetic latitudes.
• Primary Science Target
• Use of latitudinal pairs of magnetometer stations
  and the cross-phase technique to remote-sense
  the temporal and spatial variations of
  magnetospheric and ionospheric plasma density
• Storm-time field line geometry and magnetospheric
  density variations at mid-lat.
• Plasmaspheric dynamics and depletion and
  refilling processes at mid-lat.
• Ionospheric density variations and MI coupling at
  low-latitudes.
• Plasmapause dynamics penetration to low-L
  during storms.
• Internal plasmaspheric density depletions at
  low-L.
• Diurnal and activity driven ionospheric profile
  variations.
• Potential for link of IHY magnetometer derived
  density variations to those observed with GPS
  inversion technique during storms (cf. John
  Foster and co-workers).
• Secondary Science Targets
• Local current systems penetration of ring
  current to mid- and low-latitudes, as well as
  mid-latitude field stretching and mid-latitude
  substorms (e.g. Pi2 timing).
• Radiation Belts L-shell penetration of Ultra-low
  frequency wave power believed to transport and
  accelerate electrons to MeV energies in radiation
  belt.

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Cross-Phase Technique.

• The cross-phase technique uses the measurements
  from two latitudinally spaced magnetometers to
  identify the local field line resonance (FLR)
  frequency at the station mid-point.
• FLR frequency inverted with 1-D model to infer
  density variations magnetospheric at mid-lat.
  and coupled M-I densities at low lat.

Courtesy of Zoë Dent.
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Mid-latitude Substorm Onset Diagnosis

• Considerable interest in the location and timing
  of magnetotail instabilities and flows
  (substorms, BBFs, etc).
• Timing possible through Pi2 wave signatures
  (automation possible e.g., Nose et al., 1999).
• Substorm location possible through magnetic bay
  substorm current wedge analysis.

H and D bays locate FAC elements.
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ULF Waves and Radiation Belt Acceleration

• Controversy surrounding MeV electron acceleration
  mechanism.
• ULF wave processes (e.g., ULF enhanced radial
  diffusion) considered important.
• Monitoring the global distribution of ULF power
  and its penetration to low-L is valuable.
• The ambient density and plasmapause location are
  also important for a range of radiation belt
  acceleration and loss processes.
• Measurements from global ground arrays provide
  unique global view of ULF and EMIC disturbances
  along drift orbit.

(From Elkington et al, 2003)
(From OBrien et al, 2003)
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IHY Magnetometer Observatories

• Each observatory would consist of a pairs
  magnetometer stations separated meridionally by
  200-300km.
• Each station would consisting of 3-component
  fluxgate magnetometer, data logger, GPS timing,
  and power source (use solar panels for remote
  locations?).
• Data retrieval method depends on available
  infrastructure
• Phone-line modem, or local internet where
  available. Cheapest option to just switch out USB
  pen-drives by hand (one day of uncompressed 1s
  magnetometer data is 2MB).
• Approximate cost of each Observatory 20k US.
• 3 component fluxgate with RS232 output 6k US
• Industrial grade data logger/PC with GPS 2k US.
• Solar Panel power system 2k US.
• Commercial fluxgates available from western
  nations. However, an excellent low-noise supplier
  also exists at the Lviv Institute in the Ukraine.
  The Ukraine benefits from export trade/tax
  agreements with some western nations to promote
  development in the former USSR (including
  Canada). The IHY magnetometer array could aid
  the development in nations such as the Ukraine
  where suitable expertise exists.
• For the CANOPUS Array, U. Alberta is developing a
  solar cell/wind generator stand-alone power
  source which could be modified for IHY use in
  developing nations with little infrastructure
  (also allows site deployment in environmentally
  magnetically quiet locations avoids problems
  with local power grid stability).

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Potential IHY Magnetometer Array Operations

• Purchase of magnetometer sensor systems with RS
  output perhaps from the developing nation of
  the Ukraine.
• UA develops GPS timed PC-based data logger
  interface for the magnetometer.
• UA develops solar-cell/turbine power source for
  the IHY Mag. Observatories.
• UA integrates systems for delivery to
  participating nation scientists.
• UA (and perhaps other western partner countries)
  organize and run a number of regional/continent
  specific deployment schools whereby developing
  nation scientists attend a single deployment.
  They then deploy their own observatories in their
  own nation on their own.
• IHY array data are more powerful than data from
  single observatory alone, although science can be
  done with a single observatories data especially
  in combination with partner IHY data sets.
• Project involvement should require data delivery
  to IHY Magnetometer Array data centre.
  Re-enforces the value and importance of having a
  central IHY data collection/storage archive/data
  centre.
• The scientific value of the collective IHY array
  data set encourages collaboration between
  participating nation IHY Mag. array scientists.
  Could provide the basis for IHY Science
  Workshops/Conference with active participation
  from the participating scientists.

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Remote-sensing Plasma Density

• Recent observations by the IMAGE satellite have
  revealed a wealth of new dynamic structure in the
  coupled ionosphere-plasmasphere system.
• Dents, plumes, striations, bifurcations, internal
  depletions, MI coupling
• Fundamental processes responsible for plasma
  injection, and redistribution and loss are not
  understood.
• Relationships between ionospheric and
  plasmaspheric plasma structure are also not
  understood.

(From Adrian et al, 2004)
(From Goldstein et al, 2004)
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Mass Density and Plasmapause Variations.