Spatially Dependent Emergence Rate

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Spatially Dependent Emergence Rate

• V. Abramenko

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Outlook

• Compare results from the paper by Abramenko,
  Fisk, Yurchyshyn
• ApJ 641 (hereafter AFY) with that from Version 1,
  Version 2,
• Version 3, and Version 4 of the paper
• by Hagenaar, Schrijver, and DeRosa
• ( hereafter HSD-V1, HSD-V1, HSD-V1, HSD-V1)
• Role of the magnetic imbalance and distribution
  functions
• Impossibility to find the unique value of the
  emergence rate,
• the tendency only (effects of resolution)

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The Rate of Emergence of Magnetic Dipoles in
Coronal Holes and Outside
Abramenko, Fisk, Yurchyshyn, ApJ 641, 2006.
(hereafter AFY paper)
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A number of dipoles that emerged during 24 hours
inside an area of 200 x 200 Mm is taken as the
Dipole Emergence Rate, m
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HSD-V1 V3 two CHs from the AFY data set
V1
V2
V3
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HSD-V1 HSD-V3 two CHs from the AFY data set
CH 2002/07/31 cadence
CH 2003/05/30 cadence
AFY N(qs)/N(ch) 1.73 3-5
hour HSD-V1 N(qs)/N(ch) 1.48 5
min HSD-V2 N(qs)/N(ch) 2.4
5.min HSD-V3 N(qs)/N(ch) 2.6 5 min
AFY N(qs)/N(ch) 1.19 3-5 hour HSD-V1
N(qs)/N(ch) 1.22 5 min HSD-V2 N(qs)/N(ch)
1.8 5 min HSD-V2 N(qs)/N(ch) 1.6 5 min
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HSD-V3 N(qs)/N(ch) 2.9
HSD-V4 N(qs)/N(ch) 0.82
Broadening of the CH boundary results in lowering
of the ratio.
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HSD V4
Averaged number of emerged bipoles per one sample
box
Magnetic flux imbalance, ?
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How the lifetime can influence the emergence rate?
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1
1
1
Low cadence N(qs)3
QS
1
1
CH
Low cadence N(ch)1
time
Low cadence N(qs)/N(ch)3/13.0
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How the lifetime can influence the emergence rate?
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1
3
Low cadence N(qs)3
QS
1
3
1
1
1
High cadence N(qs)3
1
CH
Low cadence N(ch)1
1
High cadence N(ch)3
1
3
1
1
time
Low cadence N(qs)/N(ch)3/13.0
High cadence N(qs)/N(ch)3/31.0
If the lifetime in CHs is predominantly shorter
then the cadence improvement results in equating
of registered number of emerged bipoles in CH and
QS.
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Relationship between the Lifetime and
FluxHagenaar et al. 1999
Biggest live longer
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Distribution of the Flux for emerged bipolesHSD
V3
QS
CH
PDF for QS displays a more heavy tail than the
PDF of CH does. Bipoles in CHs are smaller than
bipoles in QS. Therefore, their lifetime is
shorter.
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• Loops inside CHs are the weakest population,
  therefore they live shorter.
• The distributions are highly non-Gaussian, the
  averaged parameters are
• not suitable, the entire distribution function
  has to be considered.

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Ratio of cummulative distribution functionsHSD
V2
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Conclusions

• For flux gt 1019Mx and for time cadence larger
  than 5 min, the bipole emergence rate correlates
  with the flux imbalance AND inside CHs it is
  smaller than outside.
• Under these restrictions, the emergence rate
  and flux imbalance are spatially dependent.
• Distribution functions of the magnetic flux
  content show that CHs are populated by closed
  loops of weaker fluxes than QS areas. This allows
  to suggest that the lifetime of loops in CHs is
  shorter than that in QS. Which might results in
  equating of number of emerged bipoles in CH and
  QS as the cadence/resolution improves.
• The emergence rate and flux imbalance are
  resolution dependent, too.
• Distribution functions are highly non-Gaussian.
  Area-averaged parameters cannot provide an
  appropriate representation for the expectation
  values of the flux content, lifetime, number of
  bipoles, etc.
• Observed distribution functions have to be
  applied to derive mean values of magnetic
  parameters.

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Solar wind speed versus the flux imbalance in a CH