Measuring Proton Energies and Fluxes Using EIT (SOHO) CCDs

Areas Outside the Solar Disk Images

L. Didkovsky1, D. Judge1, A. Jones1, and J. Gurman2

1USC Space Sciences Center2 Goddard Space Flight Center

We Propose• To use SDO CCD areas outside the solar disk images

for extracting information related to proton energies, fluxes, dynamics, asymmetries, etc., for SEPs associated with powerful CMEs and X-class flare events. The typical proton energy ranges above 40 MeV (SOHO/EIT data) are substantially narrower than available from the GOES database, e.g., 45 – 49, 145 – 154, 195 – 234, 297 – 335, and 390 – 440 MeV. SDO CCDs may allow us to extract SEP data with a substantially higher cadence than EIT and in a number of narrower energy ranges using a differential technique.

Why We Propose To Study SEPs“Why haven’t we made more progress in

understanding SEP events?”, - T. von Rosenvinge (Chapman Conference on Solar Energetic Plasmas and Particles, 2004, Finland)

• Relation to solar flares and CMEs? • Acceleration mechanisms: when and how they

work? Shock waves / Magn. Reconn., D.E. Innes, Nature, 1997

• Relativistic properties?• Details of energy spectra?• Isotropic vs. anisotropic (e.g. ERNE event of

1996/07/09: 25-40 deg FWHM)?

How To Study SEPs• GOES-8,10,11 database (40, 80-165, 165-500

MeV).• ERNE/SOHO (saturated by extreme events).• A Project based on a few space platforms,

observing SEPs at different distances to the Sun (B. Lin “The living with a star (LWS) sentinels mission”, SPIE 5901, 2005), is under development.

• Extract SEP fluxes and proton energies in a number of narrower (than GOES) energy ranges (current work). E.g., Didkovsky et al. Astron. Nachr. / AN, 327, No.4, 314, (2006).

Extracting Proton Events (Jan 20, 2005)

W E

S

NOAA 10720

Original SW areaOf 128 x 128 pix

One-pix eventsIntensity showsproton depositedenergy

One-pixel Events and CCD Deposited Energy

Angles of incidence (spatial areas) to create one-pixel events into

21x21x12 m EIT CCD

Energy Ranges

E (MeV):• 45-49 (47)• 145-154 (150)• 195-234 (220)• 297-335 (316)• 390-440 (415)

GOES and EIT Proton Spectra

The largest low-energy flux and the largest trend: 10/28

The largest high-energy flux, the smallest trend, and the smallest time delay from the X-ray peak: 01/20

Bastille Day SEPs Extracted From EIT

An example of extracted from EIT (thick lines) proton fluxes in four energy ranges of 47, 150, 316, and 415 MeV compared to the GOES (thin lines) database. Dotted line shows GOES X-ray flare profile for reference in arbitrary units. Some dropouts are due to a low statistics of the SEP events.

Time-delays Vs Energy

Proton Flux Anisotropy (Ratio One-pix/other)

10:48:10 (415 MeV)

11:00:10 (415 MeV)

Concentration in space/time

47 MeV

Wind Satellite data (http://lepmfi.gsfc.nasa.gov/mfi/)

Proton Flux Anisotropy

Concentration in space

Concentration in time

Conclusions• Extracting proton energies and fluxes from EIT

CCD areas outside the solar disk images is a new and powerful tool for our better understanding of SEP generation, acceleration, and relation to the solar flares.

• A modeling of proton energy deposition / stopping power for a number of SDO CCDs may be started now if there is a strong interest in converting the “painful noise” of the solar observations into important knowledge about SEPs.

• Software developed to extract SEP-associated events from SDO CCDs may be used to clean up the solar images from the particle-related noise.