The science targets of the SCOPE mission

Masaki FujimotoISAS, JAXA

The solar system, the natural laboratory for space plasma

• Formation of planetary magnetospheres via interaction between the solar wind and the planet’s intrinsic magnetic field

• Dynamics behavior of plasma in the magnetospheres

The same is true for the earth’s magnetosphere

• Aurora. Its attractive behavior reflects the dynamism of the plasma in the earth’s magnetosphere

Earth and planetary magnetospheres:The point of view

• Interest in itself.

Earth and planetary magnetospheres:The point of view

• Interest in itself.

• The laboratory of space plasma dynamics

• The only field where in-situ measurements of particles and fields can be made.

Magnetospheric physics: The new stage

• “The Plasma Universe”

• “The Magnetic Universe”

The question

What makes the cosmic gas to behave so dynamically?

#Looking through the earth’s magnetosphere at the Plasma Universe

Plasmas throughout the Universe

What SCOPE can do to establish the Plasma Universe concept

• Perform unprecedented in-situ observations targeted at

shocks, reconnection, and turbulence. • The target physical processes are of

fundamental importance in the universal context, and are operative in the earth’s magnetosphere.

• Construct hands-on-data basis towards the fundamental understanding of the processes.

• Critical knowledge that can come only through in-situ observations.

The MHD way of looking at space plasmas

• MHD Approximation

　 - Gas motion under the influence of magnetic field and electric currents

- The gas motion twists the field lines.

- A new spatial distribution of electric currents are set up.

　 - Gas motion is altered.

- (refrain)

Electric currents in space

• J = rot B in MHD

• J is determined by the spatial structure of B. No problem in producing whatever current density required.

• J = rot B in MHD• J is determined by the spatial structure of B. No

problem in producing whatever current density required.

??!

Electric currents in space

• J = rot B in MHD• J is determined by the spatial structure of B. No

problem in producing whatever current density required.

• In reality, J reflects differential motion between ions and electrons, namely, J=en(Vi-Ve).

• A mechanism (non-MHD physics) is needed when extremely large current density (thin current sheet) is required.

• Onset of non-MHD effects in a thin current sheet embedded in the MHD-scale dynamics that pinches the current sheet: This is where most of the wonders in space plasmas originate!

Beyond MHD

• MHD is useful but misses the most attractive part of space plasma physics

• We are determined to step forward and to construct a new framework that truly captures the attraction

• SCOPE will generate hands-on-data basis for the new framework.

　

　　　

　　　　

The only field where detailed in-situ measurements

of the complicated physical system is possible

The target physical processes

Shocks, reconnection,

and turbulence:

Shocks

• Shocks themselves are fluid-dynamical entities

• In space physics, shocks are said to be particle accelerators

• Fluid versus particle?!

The energy spectrum of cosmic ray

Particle acceleration at shocks

ＳＮ R１００６

Shocks: ordinary fluid-dynamics versus space plasma physics

UpstreamFast and cold, Maxwell distribution

Very thin transition layer, where viscosity is effecttive

DownstreamSlow and hot, Maxwell distribution

Explosive magnetic reconnection

In the night-side magnetosphere,

Large scale current sheetpinching motion

Thin current sheet foramtion,onset of electron scale dynamicsWithin it.

Maturing of the reconnection engine(diffusion region)

Creation of reconnection jet

Jet interacting with the surrounding plasma

Set-up of auroral current system

Production ofenergetic particles

Theory “predicts” very curious behavior of collisionless plasma. Is it truly happening in the real space plasma? We won’t identify ourselves understanding it until we “see” it in the data.

Turbulence

• Turbulence is something you cannot get away from if you are interedted in non-linear fluid/gas dynamics

• The addition of the magnetic effects adds even more complication in space plasmas

• One of the fundamental problem in space plasma physics, particle acceleration, is closely related with turbulence.

Magnetic field, collisionless system, dynamical coupling among different scales

• Cascade power at short wavelength viscous dissipation: Ordinary picture

• Cascade power at short wavelength New terms start to dominate giving rise to new effects: Space plasmas

Space plasma turbulence

k

Power

Energy cascase

MHD-scale

Ion-scale

Electron-scale

Non-MHD effects arise as cascade proceeds

Magnetic field, collisionless system, dynamical coupling among different scales

• Cascade power at short wavelength viscous dissipation: Ordinary picture

• Cascade power at short wavelength New terms start to dominate giving rise to new effects: Space plasmas

• Background (zero-th order) inhomogeneity supported by magnetic field is ubiquitous

Dipole-tail current sheet transition region

Shocks, reconnection, and turbulence

MHD phenomenon as a whole.

MHD does not let you truly understand what you are attracted to in space plasma physics

It is the coupling between MHD-scale dynamics and non-MHD (ion and electron scale physics)that is crucial for the fundamental understanding of space plasma dynamics

What SCOPE can do to establish the Plasma Universe concept

• Perform unprecedented in-situ observations targeted at

shocks, reconnection, and turbulence.

What exactly is this?

• Perform unprecedented in-situ observations targeted at

shocks, reconnection, and turbulence.

Simultaneousmulti-scale observations

Cross Scale CouplingMHD-scale dynamics

Key process in key region

In most cases, ion/electron scale physics

Non-linear effects

Non-MHD processes add interestingeffects unreachable by MHD dynamics

Boundary condition

Addition of curious effects Large-scale Dynamic

phenomenon develops only when the system works

as a whole

Simultaneous multi-scale measurements

• Zoom-in to the electron-scale and monitoring ion/MHD-scale dynamics at the same time

# Large FOV and high-resolution pixels at the same time, in the case of imaging.

SCOPE

Shock wave

Magnetic Reconnection

Boundary Layer TurbulenceProcesses of fundamental importance in the Plasma Universe

Turbulence　 atdipole-current sheet transition region

The science questions of SCOPE

• Shocks

• Reconnection

• Turbulence

Shocks

• How does a shock dissipate and distribute the upstream kinetic energy?

• What is the role of the extended turbulent region upstream of a shock front due to the collision-less nature of the plasma?

• How does a shock accelerate particles to high energies?

Reconnection

• How is reconnection triggered?

• How does the energy conversion in reconnection progress?

• How does reconnection produce non-thermal particles?

Turbulence

• How does turbulence transport energy over multiple scales?

• How does turbulence lead to anomalous transport of plasma?

• How does turbulence interact with the background non-uniformity to produce anomalous transport?

The worst question you can ever think of:

“Will SCOPE just confirm what theorists predict?”

• The key issue: How does the system act locally in response to the requirement J = rot B given by MHD-scale dynamics

• Collisionless plasma: Almost infinite degrees of freedom in the distr. fn. shape that satisfies

J=en(Vi – Ve)

• How Nature makes the choice is the question.

• You just cannot convince yourself until you “see the data in your hand”.

Simulation studies and SCOPE

• Due to computational resource limitations, one should think that simulation results are suggesting possibilities but nothing more.

• At the same time, one should be excited to see in the simulation results how curious space plasmas can possibly behave.

• Then one should be motivated to dig into the data to discover that is very exciting, or plan a mission that will produce very exciting data.

• Likewise simulation studies are occasionally directed by data analysis studies.

• In any case, most simulationists (at least in JP) will invest their efforts in multi-scale simulations for the next ~10 years.

SCOPE: The mission

Daughter(far) ： 5km 〜 5000km

Daughter(far)

Daughter(far)

Mother

Daughter(near) ： 5km 〜 100 ｋｍ

Daughter(far)

MHD Scale

Ultra high-speed electron measurements

Electron Scale

SCOPE-Original

Mother-NearDaughter pair

• As good as/bettter than the MMS s/c• FESA: 10 msec ele detection in the magnetotail

(100 times higher sensitivity than MMS)• MEP: Covers 10~100 keV energy range continu

ously• Wave-particle correlator• Sun-pointing spin axis of ND: Precise measurem

ents of north-south DC E-field component • Inter-s/c distance <100km: Electron-scale pair

FarDaughters

• More or less a standard spacecraft (~150kg)• 3-component E&B wave measurements on all s/

c enabling quantitative analysis of the wave energy flow

• Inter-s/c distance <100km ~ 5000km

Electron~ion~MHD scales

M-ND pair@electron scale + FD@ion/MHD

simultaneous multi-scale obs.

Obs. supporting systems

• Inter-s/c comm. for localization, time-synchronization, commanding, and data link for intelligent coordination

• Large volume data storage

• Spin axis antenna

Right size budget?

• M-ND by JAXA

• FD by CSA

• SIs onboard SCOPE by JAXA-CSA led consortium

• Launcher = H2A: More capability than ISAS science program can afford to fill

NASA as the dual-launch partner

The toughest question

• Is the number of the s/c outside the mother-daughter pair, three, good enough?

• Two-scales at the same time, at most.• More straightly, more is not only better but is differ

ent.

International collaboration helps.

The whole picture of SCOPE/Cross-Scale:

Full-scale coverage via international collaboration with clear interfaces

ESA’s component Cross-Scale

China’s component Russia’s component

To be launched by JAXA’s H2-ASCOPE mother and near/far-daughter (JAXA) Far-daughters (CSA)

Dual launch partner THEMIS-like s/c (NASA)

The status of SCOPE

• Passed MDR in Jan 09

• Ready to move on to Phase A (another review expected in May 09)

• Intense collaboration with CSA started

• Need to accelerate the study on the NASA component

• SCOPE/Cross-Scale MUST happen with the full-scale international collaboration scheme.

The whole picture of SCOPE/Cross-Scale:

Full-scale coverage via international collaboration with clear interfaces

ESA’s component Cross-Scale

China’s component Russia’s component

To be launched by JAXA’s H2-ASCOPE mother and near/far-daughter (JAXA) Far-daughters (CSA)

Dual launch partner THEMIS-like s/c (NASA)

Hey, how about Taiwan?!