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HILARY CANE Bruny Island

HILARY CANE Bruny Island. RADIO SPECTROMETER. Ian Richardson and Tycho von Rosenvinge NASA/GSFC. SOLAR ENERGETIC PARTICLES (SEPs) What we know (observe) and what is under debate. OBSERVATIONS. ASSOCIATIONS INTENSITY-TIME PROFILES ANISOTROPIES TIMING CHARGE STATES SPECTRA

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HILARY CANE Bruny Island

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  1. HILARY CANE Bruny Island 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. 30 mins 1960’s to 1980’s 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 H alpha Nonthermal electrons ≤200 keV and ~MeV Soft Xrays Hard Xrays Gamma rays Electrons (20 keV-1 GeV), protons (up to ~10GeV) and ions (up to ~100 MeV/nuc) Impulsive Gradual phase Phase

  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. Coronagraph W26 Meter wavelength dynamic spectrum Soft Xrays

  16. W

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

  18. SCATTER FREE

  19. SCATTER FREE ELECTRON EVENT

  20. An event from the east limb

  21. 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”

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

  23. 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

  24. CHARGE STATES >10 MeV/nuc

  25. 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.

  26. 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.

  27. “Two classes of solar energetic particle events …..” CANE, MCGUIRE AND VON ROSENVINGE ApJ1986

  28. DAILY AVERAGED INTENSITY OF OXYGEN VS. THAT OF IRON AT 1.9-2.8 MEV/NUC FROM ISEE-3 (LAUNCHED 1978) Reames (1990)

  29. BIMODAL?

  30. Reames (1992)

  31. 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.

  32. 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”.

  33. 0.25-0.7 MeV Electrons 0.67-3.0 MeV “ 25.9-32.2 MeV Protons 50.8-87.3 MeV “ 25.9-32.2 MeV/n Helium 50.8-67.3 MeV/n “ 0.32- 0.64 MeV/n Oxygen 1.28-3.07 MeV/n “ 14 MeV /n “ 34 MeV/n “ 0.32- 0.64 MeV/n Iron 1.28-3.07 MeV/n “ 14 MeV /n “ 34 MeV/n “ Example of a small (electron-rich) event observed by instruments on ACE and SOHO.

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

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

  36. 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)

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

  38. ARGUMENTS AGAINST POSSIBILITY OF FLARE PARTICLES IN “GRADUAL” EVENTS 1 Flares particles cannot escape 2Flare 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

  39. ARGUMENTS AGAINST POSSIBILITY OF FLARE PARTICLES IN “GRADUAL” EVENTS 1 Flares particles cannot escape 2Flare 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

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

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

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