Review of Observations of Particles From Solar Flares and Their Clues to the Structure of the IMF Joe Mazur The Aerospace Corporation Glenn Mason Johns.

Review of Observations of Particles From Solar Flares and Their Clues to

the Structure of the IMFJoe Mazur

The Aerospace Corporation

Glenn Mason

Johns Hopkins/APL

Joe Dwyer

Florida Institute of Technology

Joe Giacalone & Randy Jokipii

University of Arizona

Ed Stone

California Institute of Technology

SHINE 2006WG3 - Turbulence

2

Introduction• Energetic ions from solar flares sometimes arrive at Earth

with velocity dispersion that allows us to see individual particle injections from active regions at the sun.

• The particle events often have drop-outs in intensity across all energies that are an effect of the structure of the interplanetary magnetic field, and not of particle release at the flare source.

• This talk will briefly review the observations and their interpretation using a model magnetic field that was developed to interpret the transport of energetic particles above the ecliptic plane via meandering field lines.


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Velocity dispersion is common to many acceleration sites

30

100

300

3:00 5:004:00 6:001990 August 21

initialinjection

drift echoes

UT

Field-aligned beams in aurora: propagation distance ~103 km

Drift echoes from substorms: propagation distance ~105 km

~10 secondsGEODESIC rocket flight data courtesy of J. Clemmons

CRRES/MICS data courtesy of J. Fennell


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Velocity dispersion in energetic particles from solar flares

0.1

1

MeV/nucleon

12

3 4

56

7891011

carbon - iron

8/15/98 8/17/98 8/19/98

• Propagation distance ~108 km

• Multiple particle injections from a solar active region

• Particle intensity often varies by >10x during an event

• Sometimes do not observe the entire injection

Mason, Mazur, & Dwyer ApJ Letters 525, L133-L136,1999


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Solar flares & escaping ions

M. Aschwanden, Space Sci. Rev. 101, 1-227, 2002

• Events have been studied since the 1970’s

• Enhanced in 3He (~1000x), Ne-Fe (~10x), trans-Fe (~1000x) compared to solar corona

• Sometimes fully stripped up to Si• Beams of 10-100 keV electrons• Gyroresonant wave-particle

interaction in a 3-5 MK plasma may account for enrichments (3He: Temerin & Roth 1992, Ne-Fe: Miller et al. 1993)


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Glimpses of small-scale (~1 hour) variations in solar energetic particles

Anderson & Dougherty, Solar Phys. 103, 165-175, 1986. Buttighoffer, Astron. & Astrophysics 335, 295-302, 1998


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Glimpses of small-scale variations in solar energetic particles

McCracken & Ness, JGR 71, pp. 3315-3318, 1966


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POSITION-SENSINGANODE

SCALE (cm)

0 10

DETECTOR ARRAYSOLID STATE

TYPICAL SECONDARYELECTRON PATH

ULEIS Telescope Cross Section

ANODEPOSITION-SENSING

THIN FOIL

TYPICAL ION PATH

ELECTROSTATICMIRROR

ACCELERATING HARP

SUNSHADE

START1 MCPs

START2 MCPs

ELECTROSTATICMIRROR

STOP MCPs

SLIDING IRIS(partly open)

Ultra-Low Energy Isotope Spectrometer

• 0.02-10 MeV/nucleon • Dual time-of-flight measurements for improved mass resolution

m/m ~ 0.03


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3He

Time

Mas

s


10

10-3

10-2

10-1

100

101 Fe 0.0342 MeV/nuc Fe 0.0683 MeV/nuc Fe 0.1366 MeV/nuc Fe 0.2733 MeV/nuc Fe 0.5466 MeV/nuc

Flux (#/cm

2

-sec-sr-MeV/n)Fe flux

10-2

10-1

100

8 8.5 9 9.5 10 10.5 11

MeV/nucleon

day of 1999

Fe energy vs time

• New views of the time-dependence of solar particle events

• Low-energy threshold so an event lasts many hours

• Large collecting area for low-intensity events that previous instruments would have missed

A new look with ULEIS sensitivity


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0.1

1

MeV/nucleon

12

3 4

56

7891011

carbon - iron

8/15/98 8/17/98 8/19/98

Puzzling cases of “missing” ions

Mason, Mazur, & Dwyer ApJ Letters 525, L133-L136,1999


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Time& spatial scales of events

• 25 events 11/97 to 7/99• Tallied duration of “sub-

intervals”• Factored in solar wind speed

to convert to a spatial size• Edges of drop-outs as sharp

as ~2 minutes (~5x104 km or ~ few gyroradii of 1 MeV/n 56Fe+18)

Mazur et al. ApJ Letters 532, L79-L82, 2000


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CME-related events

• Events associated with large coronal mass ejections do not have drop-outs

Reames et al., ApJ, 466, 1996


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0

5

10

15

20

25

0 4 8 12 16 20 24

counts/bin

sub-interval duration (hours)

solar energeticparticles: mean = 3.2 hours

solar wind: 3.4 hours

02468

101214

0 4 8 12 16 20 24 28

counts/bin

sub-interval size (106 km)

solar energeticparticles:

mean = 4.7x106 km

solar wind:

4.9x106 km

Survey results

Solar wind correlation length: Matthaeus, Goldstein, & King, JGR 91, 59-69, 1986


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Suprathermal electrons

Gosling et al. ApJ 614, 412-419, 2004

• Common features in ions and suprathermal electrons (<1.4 keV) (akin to electron obs. of Anderson & Dougherty 1986)

• Gosling et al. (2004) showed 2 events where the ions had dropouts but the electrons did not, possibly indicating a more uniform and/or broad electron source

ions

electrons


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-200

-150

-100

-50

0

50

100

150

200

-100 0 100 200 300 400Xgse

~265 Re

Wind

ACE

solar wind~550 km/sec

Delay from ACEto Wind ~ 50 minutes

12 August 2000

•Simultaneous observations of the same flare injection on 12 August 2000: ACE & Wind spacecraft

•The later arrival of empty flux tubes at Wind is consistent with solar wind convection

UT

Simultaneous Wind/ACE observations

C-Fe

C-Fe


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Numerical simulations of particle transport

• Model field used to study propagation of particles from corotating interaction regions to high heliographic latitudes (Giacalone 1999)

• Model was based on earlier work by Jokipii & Parker (1968) and Jokipii & Kota (1989)

• Random motion of field line footpoints in the photosphere over ~4x104 km, time scales of ~1 day


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Giacalone, Jokipii, & Mazur, ApJ Lett. 532, 2000

•The model followed the trajectories of 8 keV/n to 20 MeV/n oxygen from an impulsive flare

•The particles traveled through pre-existing IMF structures

•After ~1 day, ions were still present inside 1 AU and populated field lines spanning ~10º in longitude


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•Simulated velocity dispersion & time-dependence with two different source sizes

•Same realization of the magnetic field

•Large sources (corresponding to a CME shock) generate continuous event profiles

Giacalone, Jokipii, & Mazur, ApJ Lett. 532, 2000


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Closer look at dropout “edges”: iron


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Closer look at dropout “edges”: iron

At 1700Z:B ~ 24 nTVsw ~ 580 km/sec

More examples, viewed with iron

Questions1. What observables in the 1 AU solar particle data might be used

to establish the source of these dispersionless features (i.e. turbulence or field-line mixing from footpoint motion at the sun)?

2. What inner heliosphere measurements of the IMF and of the energetic particles, on Sentinels for example, would clearly establish the origin of these features?

3. Are the Ulysses observations of Jovian electrons as far as ~2 AU from Jupiter (McKibben et al. 2006) a valuable constraint on either the turbulence or random walk model?

4. What other observables in these data would be of use? (solar cycle dependence; statistics of the scale of the ‘dropout’ edges)


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New Capability: Advanced Composition Explorer

• ACE launched in August 1997

• The ACE objective is to collect samples of matter in the solar system using large instruments

• We do the collecting by letting the matter come to ACE and transmitting the results to Earth


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3He-rich Solar Flares

• Discovered in late 1960s• 3He/4He ratio in solar wind ~5x10-4

• The events drew attention because 3He/4He> 0.1 without any accompanying 2H or other secondaries as one might expect from spallation in the solar atmosphere

• Later found enhancements of heavy ions up to iron by factor of 5-10 as well as: – Impulsive electron events– Scatter-free propagation– Often lack of any flare association on Sun– Sometimes ions fully stripped of electrons

Mason et al. ApJ 574, 1039--1058, 2002

3He4He


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ACE Survey of Flare Spectra• Searched for periods with clear

flare velocity dispersion– Deleted events with local acceleration– Required complete observation of

event (i.e. that ACE remained connected to it) for whole energy range of instrument

• Cases often involved multiple injections; each event separated, and fluences calculated

Mason, Dwyer, & Mazur ApJ Lett. 545, 2000

Review of Observations of Particles From Solar Flares and Their Clues to the Structure of the IMF Joe Mazur The Aerospace Corporation Glenn Mason Johns.

Documents

wg3 turbulence

fennell slide

solar corona

time mass slide

uleis sensitivity slide

solar wind speed

lowintensity events

particle release