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MotivationCoronal signatures

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Bottom is at 64 seconds; top is at ~20 hrs. We have fitted to the range indicated, because this best correlates with the usual Joseph effect Introduce memory via ... – PowerPoint PPT presentation

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Title: MotivationCoronal signatures


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Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
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Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
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the solar wind
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
natural turbulence laboratory
  • We aim to
  • Compare turbulence in plasmas and neutral fluids
    so that we can learn more about the universal
    aspects of turbulent flows
  • Specific understanding of plasma turbulence
    phenomenology and modeling of space weather
  • Learn more about the conditions in the solar
    corona from which the solar wind originates.

High magnetic Reynolds number 105
5
the solar wind
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
natural turbulence laboratory
  • We aim to
  • Compare turbulence in plasmas and neutral fluids
    so that we can learn more about the universal
    aspects of turbulent flows
  • Specific understanding of plasma turbulence
    phenomenology and modeling of space weather
  • Learn more about the conditions in the solar
    corona from which the solar wind originates.

High magnetic Reynolds number 105
6
the solar wind
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
natural turbulence laboratory
  • We aim to
  • Compare turbulence in plasmas and neutral fluids
    so that we can learn more about the universal
    aspects of turbulent flows
  • Specific understanding of plasma turbulence
    phenomenology and modeling of space weather
  • Learn more about the conditions in the solar
    corona from which the solar wind originates.

High magnetic Reynolds number 105
7
self-similarity
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
Change scale from t to bt AND scale y to bHy
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self-similarity
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
Change scale from t to bt AND scale x to bHx
If the statistics of bHy is the same as y then
process is statistically self-similar
Hurst exponent H
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Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
x(t,?) y(t?) - y(t)
?
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Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
x(t,?) y(t?) - y(t)
?
probability density function (pdf)
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pdf collapse
Motivation Coronal signatures Scaling Introducin
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pdf collapse
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
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moment scaling
Motivation Coronal signatures Scaling Introducin
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pdf scaling implies scaling of moments AND
monoscaling implies a linear increase in the
scaling of the moments with moment order p
?(p)Hp
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moment scaling
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
pdf scaling implies scaling of moments AND
monoscaling implies a linear increase in the
scaling of the moments with moment order p
?(p)Hp
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Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
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Lévy processes
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
For Levy H1/?
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heavy-tails
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g memory Heavy-tails Summary
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finite-size effects
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
From extreme value theory (EVT)
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finite-size effects
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
From extreme value theory (EVT)
gradient1/?
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Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
K. Kiyani, S. C. Chapman and B. Hnat, Phys. Rev.
E 74, 051122 (2006)
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multifractals
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
non-linear
Why does this happen?
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multifractals
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
non-linear
Why does this happen?
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digression
Nigel Goldenfeld. Roughness-induced criticality
in a turbulent flow. Phys. Rev. Lett. 96,
0445031-4 (2006)
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Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
real-world data
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solar cycle change
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
  • In situ data from solar wind monitors ACE WIND
    around the Sun-Earth L1 point (R. Lepping, K.
    Ogilvie)
  • To study solar max (2000) and solar min
    (1996)
  • Probe in detail the scaling of B2 - magnetic
    field energy density

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Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
Monofractal Lévy process
Multifractal p-model
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results
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
2000 - Solar max
1996 - Solar min
?(p)
?(p)
Moment p
Moment p
H 0.44 0.02
K. Kiyani, S. C. Chapman, B. Hnat and R. M.
Nicol, Phys. Rev. Lett 98, 211101 (2007)
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Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
_at_ 1
1 year (2000 solar max) ACE 64 seconds calibrated
magnetometer data (R. Lepping)
2 hrs
5 mins
log10(Sp)
K. Kiyani, S. C. Chapman, B. Hnat and R. M.
Nicol, Phys. Rev. Lett 98, 211101 (2007)
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pdfs
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
Functional form of pdf different at solar max and
min
Power law tail at solar maximum reminiscent of a
Lévy process
B. Hnat et. al. , Geophys. Res. Lett. 34, L15108
(2007)
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Lévy?
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
H1/? for a Lévy process
Measured values H0.44 ? 1/?0.71
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Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
All epistemological value of the theory of
probability is based on this that large scale
random phenomena in their collective action
create strict, non-random regularity. (Gnedenko
and Kolmogorov, Limit Distributions for Sums of
Independent Random Variables)
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limit theorems
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
Central Limit Theorem (De Moivre, Laplace,
Lyapunov)
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limit theorems
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
Central Limit Theorem (De Moivre, Laplace,
Lyapunov)
Generalized Central Limit Theorem (Lévy)
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Joseph effect
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
Introduce memory via Mandelbrots notion of
Joseph (memory) and Noah (large events) effects
using
Linear fractional stable motion (lfsm)
Memory parameter d H - 1/?
tail parameter ?
dgt0 gt persistence dlt0 gt anti-persistence
self-similarity parameter H Hurst exponent
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lfsm
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
fft based algorithm obtained from S. Stoev and M.
Taqqu (fractals 2004)
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finite-size scaling
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
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finite-size scaling
Motivation Coronal signatures Scaling Introducin
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?(p)
Moment p
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Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
2000 - Solar max
lfsm H0.44 ?1.4
?(p)
?(p)
Moment p
Moment p
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conclusions
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
  • We find a unique monofractal signature in the
    solar wind at 1 AU in the ecliptic at solar
    maximum.
  • Use of a robust statistical estimator which
    operationally excludes a small percentage of
    poorly represented extreme events.
  • Solar Max -- Complex topology larger events gt
    are we seeing remnants of solar activity?
  • To obtain a more complete picture it is
    necessary to take into account non-Markovian
    effects

Possible signatures of the processes driving the
turbulence?
  • Outlook - look to different spacecrafts to scan
    interplanetary solar wind to study the evolution
    of its turbulence. Check for detailed solar cycle
    dependence.

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references
Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
  • Self-similar scaling of B2
  • K. Kiyani, S. C. Chapman, B. Hnat and R. M.
    Nicol, Phys. Rev. Lett 98, 211101 (2007).
  • B. Hnat, S. C. Chapman, K. Kiyani, G. Rowlands
    and N. W. Watkins, Geophys. Res. Lett. 34,
    L15108 (2007).
  • Conditioning extreme events
  • K. Kiyani, S. C. Chapman and B. Hnat, Phys. Rev.
    E 74, 051122 (2006).
  • Applications to anomalous transport
  • G. Zimbardo, Plasma Phys. Control. Fusion 47
    B755-B767 (2005).
  • D. F. Escande and F. Sattin, PRL 99, 185005
    (2007).
  • Reading on stable processes
  • Samorodnitsky Taqqu, Stable Non-Gaussian
    Random Processes.

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Motivation Coronal signatures Scaling Introducin
g memory Heavy-tails Summary
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