# Presentation: 948592

## Examples of GOES Proton Events

- Halo /May 22 0326 UT
- May 22/0354 C5/DSF
- S19 W56

- W /Aug 24 0127 UT
- Aug 24/0112 X3/1F
- S08 W90  10069

- http://www.sec.noaa.gov/ftpmenu/plots/2002_plots/proton.html

**ACE shock**
**300% in B**
**10 15 UT**

## Longitudinal Distributions of SEPs

*Reames et al. 1996*

##  Ulysses observations provide another  basis for comparison~ 10 MeV Proton Intensities at 1 AU (Wind, above) and 5.3 AU (Ulysses, below)

- Comparing the fourth largest peaks at each spacecraft suggests intensity I decreases as r**-3.7**

**Radial Variations **
**of Peak I and F for SEP Events**

- Hamilton et al. (1990) studied 5 multispacecraft events at 10 - 20 MeV:
-    1) peak intensities I decreasing as r **-3.3**
-     2) fluences F where F = 4f(E,,t)ddEdt decreasing as r **-2.1**

*Lario et al. 2000*

## Invariant Spectra

**Invariant Spectra**

- Proton spectra of large gradual SEP events show spatial and temporal
- invariance over broad ( 160o) longitude ranges ordered by shock location.

- SEP event of
- 1 March 1979
- observed at
- Helios 1 & 2
- and IMP 8

- SPATIAL
- INVARIANCE
- TEMPORAL
- INVARIANCE

*Reames et al. 1997*

## Streaming-Limited SEP Intensities

- Plateau intensities of 4.2-8.7 MeV protons from the *GOES* spacecraft and of 3-6 MeV from Helios 1 and 2.

- 1010 p/cm2 an upper limit to fluence F? Yes - Streaming limits of model of Ng & Reames (1994) of 102 p/cm2ssrMeV with 3 day duration and E-3 spectrum yields 109 p/cm2

- Superposed intensity-time profiles of 3-6 MeV protons observed by *Helios* *1* for six large events. Streaming-limited flat profiles are seen early in the events. Shock peaks are seen to arrive later in several of the events.

*Reames 1990*

*Reames & Ng 1998*

## Inner Heliospheric Sentinels (IHS)

**Time to revisit the inner heliosphere!**
-   Helios 1  0.31 to 1 AU (1974-1986)
-   Helios 2  0.29 to 1 AU (1976-1980)
- Pioneer Venus Orbiter  0.72 AU (1978-1988)

- From 2003 NASA SEC Roadmap, p.83
- See also:
-    PASO (Particle Accelerator Solar Orbiter)
-    Solar Probe
-    Solar Orbiter
-    Solar Polar Imager

**IHS – 4-Spacecraft System**

- Multispacecraft Heliospheric Mission is Moderate Program Rank # 4 in the NRC Decadal Research Strategy in Solar and Space Physics

## Basic Correlations of CMEs/SEPs

**General correlation of SEP**
**peak intensity I****P ****with CME **
**speed on log-log plot**
**Plane of sky CME speed is **
**only a crude indication of the**
**associated shock speed.**
**CME widths also important.**

**Basic Correlations of CMEs/SEPs**

- We have no good case of a gradual SEP event without an associated fast CME

- Helios study of 22 3-6 MeV
- SEP events found these
- correlations:

- IP and CME speed	   		r = 0.54
- IP and average transit shock speed	r = 0.72
- IP and in situ shock speed		r = 0.82

*Kahler 2001*

## CME Shock Fronts?

- 7 APRIL 1997 CME

- SEPS are accelerated
- at shock fronts ahead
- of CMEs
- Locations and speeds
- of white light shock
- fronts may be visible
- in coronagraph images

**CME Shock Fronts?**

## SEP/CME  ASSOCIATIONS (CONTINUED)
CMEs of higher speeds more likely to have SEP associations

**SEP/CME  ASSOCIATIONS (CONTINUED)**
**CMEs of higher **speeds more likely to have SEP associations

- _Integral_ plot of all CME speed
- distributions versus those that
- drive _strong_ IP shocks shows
- increasing probability of shock
- association with increasing
- CME speed.

**Comparison of 29 Helios shocks **
**and 3-6 MeV SEP events found:**
- _                                         _
- _ __V__tran__ speed         SEP event_
-    < 500 km/s	  none
- 500-750 km/s       occasionally
- _   __> 750 km/s            always_______  _

*Kahler 2001*

## Shocks Produce Spectral Knees

**Shocks Produce Spectral Knees**

- Shock theory (*Ellison & Ramaty 1985)*
- predicts a spectrum of the form
- F(E) = C(E2 + 2ME) -   exp(-E/E0).
- The exponential rollover at
- high energy can result from
- finite lifetimes or shock sizes.
- The rollover is observed to
- vary considerably among
- SEP events.

- 1989 September 29              1998 April 20
-        E0 = 1 GeV                     E0 = 15 MeV

*Reames et al. 2001*

- Two events with similar
-  source locations and
-  associated CME speeds

## Examples of GOES Proton Events

- Halo /Jun 17 2230 UT
- Jun 17/2255 M6
- S08 E61   10386

- Halo /May 28 0050 UT
- May 28/0027 X3/2B
- S07 W17   10365

- http://www.sec.noaa.gov/ftpmenu/plots/2003_plots/proton.html

**ACE shock**
**150% in B**
**11 55 UT   **

**ACE shock**
**100% in B**
**18 25 UT**