Transcript The Magnetospheric Multiscale Mission Jim Burch Southwest Research Institute San Antonio, TX 2008 Huntsville Workshop: The Physical Processes for Energy and Plasma Transport Across Magnetic Boundaries October 27,

The Magnetospheric
Multiscale Mission
Jim Burch
Southwest Research Institute
San Antonio, TX
2008 Huntsville Workshop: The Physical
Processes for Energy and Plasma Transport
Across Magnetic Boundaries
October 27, 2008
Universal Significance of
Reconnection
•
In general, reconnection is a candidate to explain any phenomena
exhibiting plasma heating, particle acceleration, magnetic field collapse,
or magnetic topology changes. This includes solar, stellar and planetary
magnetic fields, solar and stellar winds, laboratory plasmas and even
planetary dynamos.
•
Reconnection is extremely important in the laboratory, especially in
limiting plasma heating in Tokamaks. Moreover, recent advances have
allowed for laboratory experiments in the collisionless regime. However,
the very small temporal and spatial scales limit the measurements that
can be made within the reconnection sites.
•
Remote sensing of these phenomena (particularly in the solar context)
provides vast amounts of information on their scale sizes, temporal
development, and energy transfer; but high-resolution in-situ
measurements are needed to determine the processes that drive
reconnection.
•
Reconnection is the most important process driving the Earth’s
magnetosphere. Groundbreaking measurements by spacecraft such as
Polar and Cluster, along with rapid advancements in numerical
simulations have set the stage for a definitive experiment on
magnetospheric reconnection.
A Fundamental Universal Process
(a)
(b)
(c)
Magnetic reconnection is important in the (a) Earth’s magnetosphere,
(b) in the solar corona (solar flares and CMEs) and throughout the
universe (high energy particle acceleration). Simulations (c) guide the
MMS measurement strategy.
Sawtooth Crashes
Sudden flattening (or crashes) of the
electron temperature profile limit
plasma heating within Tokamaks,
thereby defeating their purpose.
These crashes are explained by
reconnection with a strong guide field
within the device as shown in
laboratory experiments.
Yamada et al. [1994]
Current
Density
Reconnection
Rate
Edegal et al. [2007]
Astrophysical Contexts
• Some of the most energetic phenomena in the
universe result from supernova explosions.
Crab Nebula
• After the explosion the star collapses into a
neutron star and often into a black hole.
• Later any nearby stars can be distorted and
drawn into the black hole trough an accretion
disk that is magnetically connected through
reconnection to the black hole and neutron star.
• The transfer of angular momentum by the
magnetic field to the neutron star results in the
ejection of jets of material from the star.
• The neutron star can evolve into a pulsar or, in
extreme cases, into a magnetar, which exhibits
very energetic flare-type emissions that, by
analogy with the solar corona, are likely
produced by magnetic reconnection.
Magnetar
Is it Laminar or Turbulent?
Standard “Petschek” model
has laminar flow with only two
field lines reconnecting at a
time.
Turbulent model, in which
many field lines reconnect at
once may be required to
explain reconnection that
rapidly progresses over vast
astrophysical distances.
A Fundamental Universal Process
[Nakamura, 2006]
Magnetospheric Multiscale Mission
• The MMS Mission science
will be conducted by the
SMART (Solving
Magnetospheric
Acceleration,
Reconnection and
Turbulence) Instrument
Suite Science Team and a
group of three
Interdiscliplinary Science
(IDS) teams.
• Launch is scheduled for
October 2014.
http://mms.space.swri.edu
MMS Science Objectives
Scientific Objective: Understand the microphysics of magnetic
reconnection by determining the kinetic processes occurring in
the electron diffusion region that are responsible for collisionless
magnetic reconnection, especially how reconnection in initiated.
Specific Objectives:
• Determine the role played by electron inertial effects and
turbulent dissipation in driving magnetic reconnection in the
electron diffusion region.
• Determine the rate of magnetic reconnection and the parameters
that control it.
• Determine the role played by ion inertial effects in the physics of
magnetic reconnection.
Important Scale Sizes
From simulations:
100,000 km
•
•
•
•
500 km
Unstable, thin current sheets have thickness < 1000 km
“Electron diffusion region” thickness is of order 10 km
Current sheet motion is typically 10 to 100 km/s
Required resolution for electron diffusion region is ~30 ms
100 km
Need for 4 Spacecraft
• To identify reconnection events we
need to have larger separations (up
to 400 km) with spacecraft in the
two inflow regions and in the two
outflow regions (blue and red
arrows).
• To determine processes
driving reconnection we need
to have smaller separations
(down to 10 km) with
spacecraft within the diffusion
region (as shown).
Orbital Phases
MMS employs two mission phases with inclination of 28
deg. to optimize encounters with both dayside and
nightside reconnection regions.
Orbital Strategy
Burst-Mode Data Acquisition
Burst-Mode Data Acquisition
Tetrahedron configuration and burst data acquisition maintained
throughout region of interest (> 9 RE day side, >15 RE night side).
Burst Mode Strategy
• MMS will have two ways of capturing burst data.
• The first involves on board assessment of data quality, the
sharing of data quality indices among the spacecraft, and the
assignment of priorities to each burst data interval (2.5 minutes
on the day side and 5 minutes on the night side).
– The 24-Gbyte on-board memory will store 960 minutes of
prioritized burst data along with survey data for downlink
once per orbit. The downlink is limited to 4 Gbits so only a
small fraction of the burst data can be sent to the ground.
• The second method involves inspection of the fast survey data
for identification of promising burst intervals that did not originally
have a high enough priority for downlink. By command these
intervals can be assigned higher priority so that they can be
downlinked on the next pass.
• The on-board burst quality triggers involve parameters such as
parallel electric fields, particle flux variability, parallel electron
fluxes, large delta-B, high fluxes of heavy ions or energetic
particles, etc.
MMS Payload
Fields (Lead: Roy Torbert, UNH)
• Search Coil Magnetometer (up to 6 kHz)
• Analog Flux Gate Magnetometer (0.5 nT/10 ms)
• Digital Flux Gate Magnetometer (0.5 nT/10 ms)
• Electron Drift Instrument (E, 0.5 mV/m, DC to 1 Hz)
• Double-Probe E- Field (0 - 100 kHz, 0.5 mV/m spin-plane, 1 mV/m axial)
Fast Plasma (Lead: Tom Moore, GSFC)
• Ion Sensor (10 eV - 30 keV)
• Electron Sensor (10 eV - 30 keV)
• High time resolution (30 ms for electrons, 150 ms for ions) using multiple
sensors with electrostatic scanning of FOV.
Hot Plasma Composition (Lead: Dave Young, SwRI)
• Toroidal tophat with TOF (10 eV - 30 keV H+, He++, He+, O+ per half spin)
• RF technique to reduce proton flux by 103 to eliminate spillover problem.
Energetic Particles (Lead: Barry Mauk, APL)
• Fly’s Eye Detector (all-sky electrons and ions to 500 keV)
• Energetic Ion Spectrometer (3D per spin with TOF mass analysis)
ASPOC (Lead: Klaus Torkar, IWG, Austria)
• S/C neutralization to <4 V as on Cluster.
MMS Spacecraft
Theory and Modeling
• Key to the success of the SMART science plan is the coupling of
theory and observation.
• The SMART Theory and Modeling Team has developed the latest
and most sophisticated numerical models of the reconnection
process.
– These models have been used to define the MMS
measurement requirements and guide mission design.
– During the development phase, the models will be refined
further, and procedures for assimilating the MMS data into the
models will be defined.
– In the mission operations and data analysis phase, the Theory
and Modeling team will work closely with the instrument
scientists to ensure optimum science return.
• Significant additional expertise and models have been added with
the selection of the three IDS teams.
Co-Investigators and Participating
Scientists
Fast Plasma
T. Moore (Lead)
T. Mukai
Y. Saito
A. Coates
A. Fazakerley
M. Collier
C. Owen
Fields
R. Torbert (Lead)
C. Russell
R. Ergun
P.-A. Lin dqvist
A. Roux
K.-H. Glas smeier
C. Kletzing
J. Quinn
O. Le Contel
Energetic Particles B. Ander son
B. Mauk (Lead)
W. Baumjohann
D. Baker
G. Paschmann
B. Bl ake
M. Andre
J. Clemmons
G. Haerendel
G. Reeves
J. Slavin
H. Spence
G. Marklund
M. Grande
A. Ericksson
S. Livi
J. Vogt
G. Le
Ion Composition
D. Young (Lead)
C. Pollock
S. Fuselier
K. Trattner
S. Livi
H. Funsten
D. McComas
F. Crary
N. Paschalidis
P. Valek
A. Ghielmetti
Neutralizer
K. Torkar (Lead)
Theory & Modeling
M. Hesse (Lead)
J. Drake
M. Hoshino
W. Matthaeus
R. Denton
T. Gombosi
J. Birn
P. Reiff
R. Nakamura
Interdisciplinary Science Teams
Andersson, Laila
Eriksson, Stefan
Goldman, Martin V.
Gosling, John T.
Lapenta, Giovanni
Newman, David L.
Parker, Scott E
Ashour-Abdalla, Maha
Berchem, Jean P.
Collier, Michael R.
Coroniti, Ferdinand V.
El Alaoui, Mostafa
Farrell, William M.
Goldstein, Melv yn L.
Klimas, Alex
Kuznetsova, Maria M.
Leboeuf, Jean-Noel G.
Peroomian, Vahe
Richard, Robert L.
Schriver, David
Vinas, Adolfo F.
Walker, Raymond J.
PI in Bold Letters
Angelopoulos, Vassilis
Bale, Stuart D.
Bonnell, John W; Co-I;
Chaston, Christopher C.
Eastwood, Jonathan P.
Fujimoto, Masaki
Mozer, Forrest
Oieroset, Marit
Peticolas, Laura
Phan, Tai D.
Shay, Michael A.
Summary
• MMS will conduct definitive experiments on the universally-important
plasma physics of magnetic reconnection.
• The four payloads will sample reconnection regions with separations
and data rates sufficient to determine the kinetic processes
responsible for magnetic interconnection and the resulting
conversion of magnetic energy to heat and particle energy.
• The most critical region to be probed is the electron diffusion region
within which specific predictions about the electric fields, currents,
and electron dynamics will be tested.
• The measurement requirements are based on theoretical results
from the latest reconnection models as well as on recent
measurements from Cluster and Polar.
• The MMS theory and modeling program will provide a bridge for
applying the magnetospheric results to the broader astrophysical
context.
After MMS?
ESA Cross-Scale Mission Study
After MMS?
ESA Cross-Scale Mission Study
MMS: 10 - 400 km
Cluster: ion scale and larger