global energetics of flares gordon emslie (for a large group of people)

GLOBAL ENERGETICS OF GLOBAL ENERGETICS OF FLARESFLARES

Gordon Emslie

(for a large group of people)

Initial Study (Emslie et al. 2004)Mode Symbol Log (Energy)

April 21, 2002 July 23, 2002

Magnetic UB

Flare

Thermal Uth

Electrons Ue

Ions Ui

CME

Kinetic UK

Potential U

SEPs UP

Methodologies

Magnetic EnergyMagnetic Energy

UB =

MethodologiesThermal PlasmaThermal Plasma

Uth = 3 ne V kT = 3 k T [EM . V]1/2 erg

• Emission measure (EM) and temperature (T) obtained from both RHESSI and GOES soft X-ray observations.

• Source volumes (V) were obtained from RHESSI 12 – 25 keV images using

V = f Vapparent = f A3/2

where f is the filling factor (assumed to be 1) and A is the area inside the

contour at 50% of the peak value.

Figure 1. RHESSI image at the impulsive peak of the 2 Nov. 2003 flare.Contours: blue: 12 – 25 keV (50%), magenta: 50 – 100 keV (30 & 70%)

Methodologies

CMECME

UK = ½ Mv2

U

= -GMM/R

• M determined from scattered brightness• V determined from rate of change of

position R

Methodologies

ElectronsElectrons

UE = A E0 F0(E0) dE0 dt

• F0(E0) determined from collisional thick target interpretation of HXR spectrum

• Depends on lower energy “cutoff” EC

The Electron “Problem”

• Efficiency of bremsstrahlung production ~ 10-5 (ergs of X-rays per erg of electrons)

Electron flux ~ 105 hard X-ray flux

• Electron energy can be 1032 – 1033 ergs in large events

• Total number of accelerated electrons up to 1040 (cf. number of electrons in loop ~1038).

– replenishment and current closure necessary

Electrical Current Issue

• Rate of e- acceleration in large flares 1037 s-1

• Associated Current 1037 e- s-1 1018 A• Width of Channel ~ 107 m

– Ampère law B = oI/2r ~ 104 T = 108 G– Faraday law V = L dI/dt ~ (o) I/ ~ 1019 V

• These are impossibly large:– e.g., (B2/8) dV ~ 1042 ergs

• Dynamic pressure ~ (nv)(mv)– ~ 10 dyne cm-2 (cf. 2nkT ~ 10 dyne cm-2)

Resolution? – Multiple Channels

• Current density j ~ 104 A m-2

• Maximum radius of current channel from(Ampère) B ~ B/r = o j r = B/ o j ~ 10 m

(Faraday) V= o L(r2j)/ r ~ 1 m (!)

Number of channels ~ 1012 (1014)

• Operating simultaneously!?

Methodologies

IonsIons

Ui = A E0 F0(E0) dE0 dt• AF0(E0)dt determined from fit to gamma-ray

observations• Also depends on lower energy “cutoff” EC (~ 1

MeV?)• Electrical current issues not as large• Impulse-momentum issues much more

important - dynamic pressure ~ (nv)(mv)– 100 dyne cm-2 (cf. 2nkT ~ 10 dyne cm-2)

Electron vs. Ion Acceleration

gives equality of ion acceleration and escape times

ED ~ 10-8 n(cm-3)/T(K) V cm-1 ~ 10-4 V cm-1 maximum electron energy ~ 1 MeV??

Methodologies

SEPsSEPs

• UP determined from direct observations of SEP fluences at 1 AU

• Assumptions:– solid-angle extent– number of particles crossings

Results (Emslie et al. 2004)Mode Symbol Log (Energy)

April 21, 2002 July 23, 2002

Magnetic UB

Flare

Thermal Uth

Electrons Ue

Ions Ui

CME

Kinetic UK

Potential U

SEPs UP

Results (Emslie et al. 2004)Mode Symbol Log (Energy)

April 21, 2002 July 23, 2002

Magnetic UB 32.3 ± 0.3 32.3 ± 0.3

Flare

Thermal Uth 31.3 (+0.4,-1) 31.1 (+0.4,-1)

Electrons Ue 31.3 (+?, -0.5) 31.5 (+?, -0.5)

Ions Ui < 31.6 31.9 ± 0.5

CME

Kinetic UK 32.3 ± 0.3 32.0 ± 0.3

Potential U 30.7 ± 0.3 31.1 ± 0.3

SEPs UP 31.5 ± 0.6 < 30

July 23, 2002 Summary

Refinement (Emslie, Dennis, Holman, Hudson 2005)

• Include Optical/EUV Continuum

• RecognizePrimary

Intermediate

Final

modes of energy




Magnetic FieldIntermediate

Final

modes of energy





Electrons, IonsFinal

modes of energy





Electrons, IonsFinal

Kinetic Energy, Radiationmodes of energy

Revised NumbersMode Symbol Log (Energy)

April 21, 2002 July 23, 2002

Magnetic UB 32.3 ± 0.3 32.3 ± 0.3

Flare

Intermediate

Thermal Uth 31.3 (+0.4,-1) 31.1 (+0.4,-1)

Electrons Ue 31.3 (+?, -0.5) 31.5 (+?, -0.5)

Ions Ui < 31.6 31.9 ± 0.5

Final

SXR Radiation UR 31.3 31.0

Total Radiation

UR > 31.7 > 31.6

CME

Kinetic UK 32.3 ± 0.3 32.0 ± 0.3

Potential U 30.7 ± 0.3 31.1 ± 0.3

SEPs UP 31.5 ± 0.6 < 30


April 21, 2002 July 23, 2002

Magnetic UB 32.3 ± 0.3 32.3 ± 0.3

Flare

Intermediate

Thermal Uth 31.331.3 (+0.4,-1) 31.1 (+0.4,-1)

Electrons Ue 31.331.3 (+?, -0.5) 31.5 (+?, -0.5)

Ions Ui < 31.6 31.9 ± 0.5

Final

SXR Radiation UR 31.331.3 31.0

Total Radiation

UR > 31.7 > 31.6

CME

Kinetic UK 32.3 ± 0.3 32.0 ± 0.3

Potential U 30.7 ± 0.3 31.1 ± 0.3

SEPs UP 31.5 ± 0.6 < 30


April 21, 2002 July 23, 2002

Magnetic UB 32.332.3 ± 0.3 32.3 ± 0.3

Flare

Intermediate

Thermal Uth 31.3 (+0.4,-1) 31.1 (+0.4,-1)

Electrons Ue 31.3 (+?, -0.5) 31.5 (+?, -0.5)

Ions Ui < 31.6 31.9 ± 0.5

Final


Total Radiation

UR > 31.7> 31.7 > 31.6

CME

Kinetic UK 32.332.3 ± 0.3 32.0 ± 0.3

Potential U 30.7 ± 0.3 31.1 ± 0.3

SEPs UP 31.5 ± 0.6 < 30


April 21, 2002 July 23, 2002

Magnetic UB 32.3 ± 0.3 32.3 ± 0.3

Flare

Intermediate

Thermal Uth 31.3 (+0.4,-1) 31.1 (+0.4,-1)

Electrons Ue 31.3 (+?, -0.5) 31.5 (+?, -0.5)

Ions Ui < 31.6 31.9 ± 0.5

Final


Total Radiation

UR > 31.7 > 31.6

CME

Kinetic UK 32.332.3 ± 0.3 32.0 ± 0.3

Potential U 30.7 ± 0.3 31.1 ± 0.3

SEPs UP 31.531.5 ± 0.6 < 30

Conclusion

• CME energy still dominant by factor of ~4BUTBUT

• Within uncertainties, rough equipartition amongst– Flare intermediate– Flare final– CME

• SEP shock acceleration <~ 10% efficient

Extension to Oct/Nov 2003 Flares (RHESSI/SOHO/TRACE group)

• Thermal and CME energetics by B. Dennis et al., N. Gopalswamy

• Electron/ion energetics to follow

CME vs. Flare Energies

0.1

1.0

10.0

100.0

1000.0

10000.0

0.01 0.1 1 10 100 1000

Total Energy (1030 ergs)

CM

E K

inet

ic E

ner

gy

(10

30 e

rgs)

SXR-Emiting Plasma TSI Increase (SORCE) Peak Plasma Energy (Upeak) Ions Equipartition

SORCE / TIM

28 October 2003 4 November 2003

23 July 200221 April 2002

Figure 5.

Figure 6. Flare Energies vs. Upeak

0.0

0.0

0.0

0.1

1.0

10.0

100.0

0.10 1.00 10.00 100.00

Upeak (1030 ergs)

Rad

iate

d E

ner

gy (

1030

erg

s)

LUpeak

LX,Upeak

Ltotal

LX,total

(ratio)

ConclusionsConclusions• Flare and CME energies are correlated for the Oct/Nov 2003 period.

• Total Flare and CME energies are comparable to within a factor of 10.

• Peak energy in SXR-emitting plasma is only ~1% of total flare energy in some cases.

• Energy radiated by SXR-emitting plasma is only ~10% of total flare energy in some cases.

• Energy in nonthermal electrons and ions can be a large fraction of the total flare energy.

• Dominant flare energy in impulsive phase may be electrons and/or ions leading to early peak in total solar irradiance increase seen with SORCE/TIM.

global energetics of flares gordon emslie (for a large group of people)

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