GLOBAL ENERGETICS OF FLARES

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GLOBAL ENERGETICS OF FLARES

• Gordon Emslie
• (for a large group of people)

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Initial Study (Emslie et al. 2004)
Mode Symbol Log (Energy) Log (Energy)
April 21, 2002 July 23, 2002
Magnetic UB
Flare
Thermal Uth
Electrons Ue
Ions Ui
CME
Kinetic UK
Potential U?
SEPs UP
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Methodologies

• Magnetic Energy
• UB

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Methodologies

• Thermal Plasma
• Uth 3 ne V kT 3 k T EM . V1/2 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.

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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)
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Methodologies

• CME
• UK ½ Mv2
• U? -GM?M/R
• M determined from scattered brightness
• V determined from rate of change of position R

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Methodologies

• Electrons
• UE A ? ?E0 F0(E0) dE0 dt
• F0(E0) determined from collisional thick target
  interpretation of HXR spectrum
• Depends on lower energy cutoff EC

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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

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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/2?r 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)

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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!?

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(No Transcript)
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Methodologies

• Ions
• 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)

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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??
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Methodologies

• SEPs
• UP determined from direct observations of SEP
  fluences at 1 AU
• Assumptions
• solid-angle extent
• number of particles crossings

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Results (Emslie et al. 2004)
Mode Symbol Log (Energy) Log (Energy)
April 21, 2002 July 23, 2002
Magnetic UB
Flare
Thermal Uth
Electrons Ue
Ions Ui
CME
Kinetic UK
Potential U?
SEPs UP
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Results (Emslie et al. 2004)
Mode Symbol Log (Energy) 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 lt 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 lt 30
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July 23, 2002 Summary
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Refinement (Emslie, Dennis, Holman, Hudson 2005)

• Include Optical/EUV Continuum
• Recognize
• Primary
• Intermediate
• Final
• modes of energy

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Refinement (Emslie, Dennis, Holman, Hudson 2005)

• Include Optical/EUV Continuum
• Recognize
• Primary
• Magnetic Field
• Intermediate
• Final
• modes of energy

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Refinement (Emslie, Dennis, Holman, Hudson 2005)

• Include Optical/EUV Continuum
• Recognize
• Primary
• Magnetic Field
• Intermediate
• Electrons, Ions
• Final
• modes of energy

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Refinement (Emslie, Dennis, Holman, Hudson 2005)

• Include Optical/EUV Continuum
• Recognize
• Primary
• Magnetic Field
• Intermediate
• Electrons, Ions
• Final
• Kinetic Energy, Radiation
• modes of energy

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Revised Numbers
Mode Symbol Log (Energy) 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 lt 31.6 31.9 0.5
Final
SXR Radiation UR 31.3 31.0
Total Radiation UR gt 31.7 gt 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 lt 30
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Revised Numbers
Mode Symbol Log (Energy) 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 lt 31.6 31.9 0.5
Final
SXR Radiation UR 31.3 31.0
Total Radiation UR gt 31.7 gt 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 lt 30
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Revised Numbers
Mode Symbol Log (Energy) 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 lt 31.6 31.9 0.5
Final
SXR Radiation UR 31.3 31.0
Total Radiation UR gt 31.7 gt 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 lt 30
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Revised Numbers
Mode Symbol Log (Energy) 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 lt 31.6 31.9 0.5
Final
SXR Radiation UR 31.3 31.0
Total Radiation UR gt 31.7 gt 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 lt 30
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Conclusion

• CME energy still dominant by factor of 4
• BUT
• Within uncertainties, rough equipartition amongst
• Flare intermediate
• Flare final
• CME
• SEP shock acceleration lt 10 efficient

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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

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Figure 5.
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Figure 5.
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Figure 5.
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Figure 5.
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Figure 5.
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Figure 5.
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Figure 5.
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Figure 6. Flare Energies vs. Upeak
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Conclusions

• 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.