Connecting Sun and Heliosphere – EPD contributions

Connecting Sun and
Heliosphere
–
EPD contributions
Robert Wimmer-Schweingruber
[email protected]
Christian Albrechts University Kiel
Kiel, Germany
for the Solar Orbiter EPD Team
rfws, ieap, cau
METIS Team meeting, Prague, 2014-10-16
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Contents
Summary of the problem...
Connecting the Sun with the heliosphere
What can EPD contribute?
Summary
rfws, ieap, cau
METIS Team meeting, Prague, 2014-10-16
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The Problem
From the Solar Orbiter Red Book:
How do solar eruptions produce
energetic particle radiation that
fills the heliosphere?
1) How and where are energetic
particles accelerated at the
Sun?
2) How are energetic particles
released from their sources
and distributed in space and
time?
3) What are the seed populations
for energetic particles?
rfws, ieap, cau
METIS Team meeting, Prague, 2014-10-16
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The Problem
To be an energetic particle, you need to be:
- injected
From the Solar Orbiter Red Book:
How do solar eruptions produce
energetic particle radiation that
fills the heliosphere?
- accelerated
3) What are the seed populations
for energetic particles?
1) How and where are energetic
particles accelerated at the
Sun?
- transported
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2) How are energetic particles
released from their sources
and distributed in space and
time?
METIS Team meeting, Prague, 2014-10-16
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The Problem
To be an energetic particle, you need to be:
- injected
Suprathermal seed particles
- accelerated
Flares, shocks, and compression
- transported
Charged particles tied to B
rfws, ieap, cau
METIS Team meeting, Prague, 2014-10-16
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The Problem
To be an energetic particle, you need to be:
- injected
Suprathermal seed particles
Origin not understood
- accelerated
Flares, shocks, and compression
Increasing role of turbulence
- transported
Charged particles tied to B
Perpendicular diffusion not
understood
rfws, ieap, cau
METIS Team meeting, Prague, 2014-10-16
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Connect Sun to heliosphere
Particles don't only get accelerated 'by the flare'!
(not only by reconnection, waves, etc.)
Shocks are efficient particle
“Shock genesis”
accelerators.
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Geometry Rules!
(but also its velocity,
compression ratio,
Mach number)
METIS Team meeting, Prague, 2014-10-16
Time
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Shock or diffusive (Fermi 2) acceleration
Turbulent structures
moving towards you
stepwise acceleration
via turbulent motions
Some particles gain energy in every reflection
(Fermi acceleration)
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This scenario ultimately
leads to the observed
power-law distribution
in energy. If the shock is
Turbulent structures large enough, it can
moving towards you
explain large events. 8
METIS Team meeting, Prague, 2014-10-16
Connect Sun to heliosphere
Transport
As we move close enough to the
Sun, we expect to observe:
- less “smearing out”
- clearer injections
- smaller events
… in other words, less influence
of transport effects.
How close is close enough?
Kallenrode & Wibberenz, 1991
rfws, ieap, cau
METIS Team meeting, Prague, 2014-10-16
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Connect Sun to heliosphere
SO & SP+
SO
rfws, ieap, cau
IUGG/IAGA 2011
METIS Team
meeting,
Session
A101 - Prague,
July 2/3 2014-10-16
10
Connect Sun to heliosphere
G
A A
M W
S tc .
e
SO & SP+
SO
I
U
E IX
T
S
rfws, ieap, cau
E
W
P
R
D
P
IUGG/IAGA 2011
METIS Team
meeting,
Session
A101 - Prague,
July 2/3 2014-10-16
11
Information from EPD
3He is preferentially accelerated
in flares (probably wave-particle
Velocity dispersion indicates rapid
interaction) → flare origin!
acceleration and good connection
→ no time for diffusion!
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METIS Team meeting, Prague, 2014-10-16
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Information from EPD
Velocity dispersion also
indicates that particles are
flowing towards observer
from the source. The flow
is anisotropic.
Velocity dispersion indicates rapid
acceleration and good connection
→ no time for diffusion!
For good connection:
→ 3He, large e/p ratio
→ velocity dispersion
→ anisotropies
→ type III radio emission
→ minimal onset delay
Such events are seen at 1
AU, albeit rarely (e.g.,
Klassen et al. 2011).
rfws, ieap, cau
METIS Team meeting, Prague, 2014-10-16
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Information from EPD
Velocity dispersion also
indicates that particles are
flowing towards observer
from the source. The flow
is anisotropic.
For good connection:
→ 3He, large e/p ratio
→ velocity dispersion
→ anisotropies
→ type II radio emission
→ minimal onset delay
This translates into measurement
requirements on EPD:
- electrons from few keV to MeV
- protons from few keV to 100 MeV
- ions from 10 keV to 100 MeV/n
- He isotopic composition
- high time resolution
- multiple fields of view (anisotropy)
Such events are seen at 1
AU, albeit rarely (e.g.,
Klassen et al. 2011).
rfws, ieap, cau
METIS Team meeting, Prague, 2014-10-16
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Summary
Injection: suprathermal particles
(STEP, SIS, SWA/HIS, SPICE, METIS/EUI (?))
Acceleration: plasma properties & turbulence
(all EPD, MAG, SWA, RPW, METIS, SPICE)
Transport: plasma properties & turbulence, source
(EPD, MAG, SWA, RPW, STIX, EUI)
Connectivity: anisotropy, dispersion, source
(EPD, MAG, RPW, SWA, STIX, EUI, SPICE, PHI,...)
Combination with other instruments is crucial.
Payload is meant to be used together, as a suite.
Combination with SP+, Earth, & other assets.
EPD provides its part of information using
different measurement techniques.
rfws, ieap, cau
METIS Team meeting, Prague, 2014-10-16
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Backup Slides
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METIS Team meeting, Prague, 2014-10-16
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Connect Sun to heliosphere
Wide spread events seen in
- ions,
- electrons,
- and 3He
This is sobering...
(can we connect S-H?)
… but also at 1 AU!
(Gomez-Herrero et al., under review)
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METIS Team meeting, Prague, 2014-10-16
(Richardson
et al., 2014)
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Connect Sun to heliosphere
Richardson et al. (2014) investigated 209 >25 MeV protons events
And found that:
1) all were accompanied by CMEs
2) 36% seen at only 1 SC, 34% at two, 17% at three, 13% unclear
3) Most intense events generally seen by > 1 SC
4) 92% of events accompanied by radio type III emissions
5) Single-SC events typically occur at well-connected SC,
Peak intensity < 10-2 (MeV cm2 s)-1, CME speeds < 1000 km/s
They present a list of possible explanations (perp transport,
coronal transport, expansive coronal shocks, EUV waves, largescale magnetic loops)
For Solar Orbiter:
→ Look for small, well-connected events (small delays)
→ Use all information available with Solar Orbiter, SP+, Earth, …
rfws, ieap, cau
METIS Team meeting, Prague, 2014-10-16
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Information about EPD
How do energetic particles behave
close to the Sun?

Which are injected?

How are they accelerated?

What influences their transport?
rfws, ieap, cau
METIS Team meeting, Prague, 2014-10-16
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Information about EPD
SupraThermal Electrons and Protons (STEP)
• Spacecraft mounted
– STEP will measure e- [2 - 100 keV],
p+ [3 - 100 keV]
• Instrument Heritage:
– STEP has direct heritage from
STEREO/STE and SEPT
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METIS Team meeting, Prague, 2014-10-16
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Information about EPD
Electron-Proton Telescope (EPT)
• Measures electrons and protons
– EPT will measure e- [0.02-0.7MeV], p+ [0.02-7MeV]
– Four view directions (in and out of orbital plane) with two
units
– EPT and HET sensors share the same Electronics Box
• Instrument Heritage:
– EPT has direct heritage from STEREO/SEPT
rfws, ieap, cau
METIS Team meeting, Prague, 2014-10-16
21
Information about EPD
Suprathermal Ion Spectrograph (SIS)
• Measures all elements from helium
to iron and samples trans-iron
elements
– Energy range: 8 keV/nuc – 10 MeV/n
(oxygen)
– Two telescopes view forward and aft
directions; single electronics box
• Instrument Heritage
– SIS has heritage from
ACE/ULEIS and STEREO/SIS
known distances
Start #2
Stop MCP
22°
FOV
SSDs
ToF
Start #1
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→ speed
E = ½ m v2
Energy
mass Prague, 2014-10-16
METIS Team meeting,
22
Information about EPD
High-Energy Telescope (HET)
– Measures e- [0.3-20MeV], p+ [10-100MeV] and
ions [10s-200MeV/nuc species-dependent]
• Four view directions (in and out of orbital plane)
with two units
• EPT and HET sensors share the same Electronics
Box
• Instrument Heritage:
– HET has heritage from the MSL/RAD instrument
rfws, ieap, cau
METIS Team meeting, Prague, 2014-10-16
23
Information about EPD
EPD will measure
electrons from 2keV – 20 MeV,
protons from 3keV – 100 MeV,
ions from 8 keV – 200 MeV/nuc
At high cadence
In up to 4 view directions (STEP: 15)
rfws, ieap, cau
METIS Team meeting, Prague, 2014-10-16
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Contents
Summary of the problem...
Connecting the Sun with the heliosphere
What can EPD contribute?
EPD – the Energetic Particle Detector
ICU
STEP
EPT
SIS
HET
Summary
rfws, ieap, cau
METIS Team meeting, Prague, 2014-10-16
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Summary
Injection: suprathermal particles
(STEP, SIS, SWA/HIS, SPICE, METIS)
Acceleration: plasma properties & turbulence
(all EPD, MAG, SWA, RPW, METIS, SPICE)
Transport: plasma properties & turbulence, source
(all EPD, MAG, SWA, RPW, STIX, EUI)
Connectivity: anisotropy, dispersion, source
(all EPD, MAG, RPW, SWA, STIX, EUI, SPICE, etc.)
Combination with other instruments is crucial.
Payload is meant to be used together, as a suite.
Combination with SP+, Earth, & other assets.
EPD provides its part of information using
different measurement techniques.
rfws, ieap, cau
METIS Team meeting, Prague, 2014-10-16
26

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