1. Ian Richardson HILARY CANE Bruny Island and Tycho von Rosenvinge
RADIO SPECTROMETER
Ian Richardson
and Tycho von Rosenvinge
NASA/GSFC

2. SOLAR ENERGETIC PARTICLES (SEPs) What we know (observe) and what is under debate

3. OBSERVATIONS ASSOCIATIONS INTENSITY-TIME PROFILES ANISOTROPIES TIMING
CHARGE STATES
SPECTRA
RELATIVE ABUNDANCES

4. WHAT IS INFERRED WHEN, WHERE AND HOW PARTICLES ARE ACCELERATED
HOW THEY GET TO THE OBSERVER
(CHARGE STATES)

5. WHAT NEEDS TO BE DETERMINED
How are particles accelerated in flares?
What are the characteristics e.g. sizes of regions on the sun that produce flare particles?
How do CME shocks evolve? e.g. size and strength with longitude and radial distance

6. WHAT NEEDS TO BE DETERMINED
What populations do shocks accelerate?
How much scattering (parallel and perpendicular) is there?
How does the scattering vary with radial distance?

7. 1960’s to 1980’s 30 mins Metre Wavelength Radio (MHz) Microwaves
H alpha
Soft Xrays
Hard Xrays
Gamma rays
Impulsive Gradual phase
Phase

8. METRE WAVELENGTH RADIO BURSTS
Drift from high to low frequencies shows presence of a disturbance travelling out from the sun
Type III – fast drift
produced by flare-accelerated electrons (2- 50 keV?)
Type II - slow drift
produced by shock-accelerated electrons ( a few keV)
Stationary type IV – Flare continuum
produced by trapped electrons
(gyrosynchrotron~1 MeV? Plasma emission keV?)

9. 1960’s to 1980’s Metre Wavelength Radio (MHz) Microwaves H alpha
Soft Xrays
Hard Xrays
Gamma rays
protons
Impulsive Gradual phase
Phase

10. DECA and HECTO METRIC RADIO
Interplanetary type II
NOW
Metre wavelength radio (MHz)
CME height
Microwaves
H alpha
Soft Xrays
Hard Xrays
Gamma rays
Impulsive Gradual phase
Phase

11. DECA and HECTO METRIC RADIO
Interplanetary type II
NOW
Metre wavelength radio (MHz)
CME height
Microwaves
Nonthermal electrons ≤200 keV and ~MeV
H alpha
Soft Xrays
Hard Xrays
Gamma rays
Impulsive Gradual phase
Phase
Electrons (20 keV-1 GeV), protons (up to ~10GeV)
and ions (up to ~100 MeV/nuc)

12. SEP EVENT ASSOCIATIONS
SEP EVENTS ARE (USUALLY) PRECEDED BY CORONAL MASS EJECTIONS and FLARES
THEY ARE OFTEN IN PROGRESS WHEN
AN INTERPLANETARY (IP) (CME-DRIVEN) SHOCK PASSES THE OBSERVER
LARGEST EVENTS ACCOMPANIED BY IP RADIO EMISSION FROM THE CME-DRIVEN SHOCK

13. RELATIONSHIP BETWEEN SEPS AND XRAY AND GAMMA RAY EMISSION WILL BE DISCUSSED IN SESSIONS TODAY AND TOMORROW

14. PROTON EVENTS AND XRAY SPECTRAL HARDENING (SHH)
2009 Th t Th t
3 ESSENTIALLY NO OPEN FIELD LINES
2 PROBABLY POORLY CONNECTED
1 SLOW SEP EVENT

15. Meter wavelength dynamic spectrum
Coronagraph
W26
Meter wavelength dynamic spectrum
Soft Xrays

16. W

17. Measurements near Earth
INTENSITY VS TIME
1, 5, 25, 70 MeV protons
Measurements near Earth

18. SCATTER FREE

20. SCATTER FREE ELECTRON EVENT

22. An event from the east limb

23. IF PARTICLES ACCELERATED AT A FLARE, ASSUMED TO BE A POINT SOURCE, AND CONFINED TO A FIELD LINE HOW DO WE SEE THEM FROM THE EAST LIMB?
CORONAL “PROPAGATION”

24. INTENSITY TIME PROFILES
IMP 8
SHOCK
ICME
5, 15, 25 MeV protons
Helios 1
Helios 2

25. TIMING
electrons
In order to compare particle onsets with solar phenomena need to be able to account for interplanetary propagation.
Would be much more reliable if observing close to the sun. Good luck PSP!!
Event to right seen at Helios 1 when at 0.38 AU and the s/c well connected to solar source. Note protons delayed relative to electrons
electrons

26. CHARGE STATES
>10 MeV/nuc

27. SPECTRA
Different functions have been fitted with a double power law seeming to be best for large events. Models are developed to try to predict the spectra. Note that the ones illustrated are fluences i.e. the total particle increase.

28. RELATIVE ABUNDANCES
From observations in the 1970s it was known that some SEP events are enhanced in heavy ions. Enhancement was more common in small events and less common in large events. Extreme enhancements of 3He relative to 4He were found in small events.

29. “Two classes of solar energetic particle events …..”
CANE, MCGUIRE AND
VON ROSENVINGE ApJ 1986

30. DAILY AVERAGED INTENSITY OF OXYGEN VS. THAT OF IRON AT 1. 9-2
DAILY AVERAGED INTENSITY OF OXYGEN VS. THAT OF IRON AT MEV/NUC FROM ISEE-3 (LAUNCHED 1978)
Reames (1990)

31. BIMODAL?

32. Reames (1992)

35. SA EVENTS / TYPE III-l
ISEE-3, launched in 1978, carried particle detectors and radio antennae and receivers. It was found that at the time of an SEP event the radio experiment saw strong, long lasting type III emission at the time when a type II burst was reported from the ground. Cane et al. (1981) called the type III-like radio bursts “shock accelerated” or later “shock associated”.
The association between strong, long lasting, low frequency type III bursts and SEP events was confirmed with Wind Waves data (Cane et al. 2002). HOWEVER it was realised that there was type III emission at times when no type II burst was seen from the ground plus the starting frequencies were higher than the backbone of the type II, when present. Thus the association with shocks was not correct. The phenomenon was renamed type III-l; Low starting frequency, Long duration and LATE.

36. It was thus suggested that particles accelerated in the gradual phase of flares can make a significant contribution in gradual particle events in contradiction to the current paradigm that “shocks do it all”.

37. MeV Electrons
MeV “
MeV Protons
MeV “
MeV/n Helium
MeV/n “
MeV/n Oxygen
MeV/n “
14 MeV /n “
34 MeV/n “
MeV/n Iron
Example of a small (electron-rich) event observed by instruments on ACE and SOHO.

40. ACE/SOHO observations of a big event at W76°.
It is Fe-rich at high energies where shock effect not important.

41. ARGUMENTS AGAINST POSSIBILITY OF FLARE PARTICLES IN “GRADUAL” EVENTS
1 Flares particles cannot escape
2 Flare particles confined to a small cone
3 Composition not quite right
4 Timing wrong- initiation times too late
5 Properties not centred on the flare

42. LONGITUDE SPREAD OF FLARE PARTICLES
Three s/c (Helios 1 & 2 and near-Earth)
Flare electron events (~1 MeV)
Three s/c 3He
Wibberenz and Cane, (2006)

43. ARGUMENTS AGAINST POSSIBILITY OF FLARE PARTICLES IN “GRADUAL” EVENTS
1 Flares particles cannot escape
2 Flare particles confined to a small cone
3 Composition not quite right
4 Timing wrong- initiation times too late
5 Properties not centred on the flare

44. ARGUMENTS AGAINST POSSIBILITY OF FLARE PARTICLES IN “GRADUAL” EVENTS
1 Flares particles cannot escape
2 Flare particles confined to a small cone
3 Composition not quite right
4 Timing wrong- initiation times too late
5 Properties not centred on the flare

46. ARGUMENTS AGAINST POSSIBILITY OF FLARE PARTICLES IN “GRADUAL” EVENTS
1 Flares particles cannot escape
2 Flare particles confined to a small cone
3 Composition not quite right
4 Timing wrong- initiation times too late
5 Properties not centred on the flare

47. CONNECTIVITY IS INDICATED BY DRIFT RATE OF TYPE III EMISSION

50. TWO HOUR DELAY
CROSS FIELD TRANSPORT?
CANE AND ERICKSON (2003)

51. STEREO A
EARTH (WIND)
STEREO B
Observations at Earth and STEREO A and B for the event on May 17, 2012.

53. CONCLUSIONS
DESPITE THE FACT THAT WE HAVE OVER 4 SOLAR CYCLES OF REASONABLE DATA COVERAGE AND TWO WITH GOOD (SPECIES AND ENERGY RANGES) THERE IS STILL MUCH MORE INFORMATION NEEDED TO UNDERSTAND THE GENERATION OF SEPS. THIS IS UNLIKELY TO BE ACHIEVED WITHOUT GOING CLOSE TO THE SUN.

54. CONCLUSIONS
DESPITE THE FACT THAT WE HAVE OVER 4 SOLAR CYCLES OF REASONABLE DATA COVERAGE AND TWO WITH GOOD (SPECIES AND ENERGY RANGES) THERE IS STILL MUCH MORE INFORMATION NEEDED TO UNDERSTAND THE GENERATION OF SEPS. THIS IS UNLIKELY TO BE ACHIEVED WITHOUT GOING CLOSE TO THE SUN.
HOWEVER PLEASE COME TO THE SESSIONS TODAY AND TOMORROW AND CONTRIBUTE TO A LIVELY DEBATE

58. SUN SUN SUN
NO CONNECTION POOR CONNECTION GOOD CONNECTION

59. Three (controversial) proposals were made based on analysis of Cycle 23 events:
That flares contribute significant particles in the majority of SEP events and that this is determined by the presence of Type III radio emissions [Cane et al., JGR 2002; Cane et al. JGR 2010 and references therein].
That the very low frequency behaviour of these radio bursts indicates whether the flare particles will reach an observer and how quickly [Cane and Erickson, JGR 2003].
That since flare particles do reach spacecraft that are nominally poorly connected there must be some interplanetary cross field transport [Cane and Erickson, JGR 2003, Wibberenz and Cane, ApJ 2006 ].

61. THREE PHASES OF PARTICLE ACCELERATION
FLARE IMPULSIVE PHASE (FIRST) FLARE LATE PHASE (SECOND)
SHOCK
CME
SHOCK ACCELERATION
THIRD PHASE

62. This event clearly has two components; the first is Fe-rich i. e
This event clearly has two components; the first is Fe-rich i.e. flare-like, the second is Fe-poor.
Even at 34 MeV/nuc OXYGEN peaks at shock passage; there was no local effect in IRON. Obviously O is more efficiently accelerated, presumably because it has a lower mass to charge ratio than Fe.
SHOCK
34 MeV/nuc
Particles/(cm2- sec- ster- MeV/nuc)

65. first GLE (Forbush)
Feb GLE (Meyer et al.)
Two phase acceleration (Wild et al.)
3He enrichment (Hiseh and Simpson)
Gamma-ray lines (Chupp et al.)
CMEs and SEPS (Kahler et al.)
Neutrons
SEP charge states
3He events and type III/electrons
Two classes
Workshop I

66. 1999 Reames and colleagues propose that high Fe charge states and enhancements of high-Z particles in certain large events are caused by electron stripping before shock acceleration.
Cliver (2000) The Reames picture implies “(1) that two quite different acceleration/transport processes can produce identical SEP composition; (2) and that the stripping process results in an Fe charge state similar to that observed in impulsive flares.
The need for such coincidences gives one pause and suggests and alternative picture: simply that flare accelerated SEPs account for the observed composition and high Fe charge states in these events……..
It is hard to argue that none of the flare-accelerated particles escape in large gradual flares

67. Pinter STIP 1977
Apr P6 to P9 183⁰
Nov P8 to flare 113⁰
Jan P8 to flare 116⁰

68. Hα