Ramiz Qudsi
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Statistical Comparison of Various Dayside Magnetopause Reconnection X-line Prediction Models
Ramiz A. Qudsi, Brian Walsh, J. Broll, Stein Haaland
Boston University, Los Alamos National Lab, Max-Planck Institute
*(qudsira@bu.edu)
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Outline:
- Region of interest
- Location of x-line
- Different models
- Data
- Results
- Discussions
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The BASICS
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Source: NASA
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Region of interest:
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[Broll et al., 2017]
Source: wikipedia
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Location of x-line: Models
Local field bisection [Moore et al., 2002]
Maximum exhaust speed [Swisdak and Drake, 2007]
Maximum magnetic shear [Trattner et al., 2007]
Maximum reconnecting field energy [Hesse et al., 2013]
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Magnetic shear [Trattner et al., 2007]:
\cos(\theta) = \left(\textbf{B}_{\rm sh} \cdot \textbf{B}_{\rm msp}\right)/ \left(|\textbf{B}_{\rm sh}| |\textbf{B}_{\rm msp}|\right)
B_{\rm rec} = |\textbf{B}_{\rm msp} \cdot \textbf{i}_{\rm xn}|
Local field bisection [Moore et al., 2002]:
Reconnection field energy [Hesse et al., 2013]:
E \propto \left(B_{\rm sh}^2 \times B_{\rm msp}^2\right)
Exhaust speed [Swisdak and Drake, 2007]:
V_{\rm A} = \left[\frac{B_{\rm sh} B_{\rm msp} \left(B_{\rm sh} + B_{\rm msp}\right)}{\left(n_{\rm p,msp}B_{\rm sh} + n_{\rm p,sh}B_{\rm msp}\right)} \right]^{1/2}
sh: magnetosheath
msp: magnetosphere
Location of x-line: Models
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DATA
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Data:
Solar
Wind
OMNI
Cooling-2001 Model
Magnetosheath
Magnetopause
Shue-1998 Model
T-96 and IGRF Model
Magnetospheric Fields
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Data
Solar Wind data: OMNI (propagated to the magnetopause)
Magnetosheath data: MMS (FPI and FGM)
Magnetospheric magnetic field: Models (T96 or T05 and IGRF)
Magnetosheath magnetic field: Models (Cooling model)
x
z
y
GSM coordinate system
Qudsi Center for Space Physics, BU qudsira@bu.edu
Methodology
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Methodology
- Look at the instances when MMS observed a jet reversal while crossing the magnetopause.
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Magnetosheath
Magnetosphere
[Broll et al., 2017]
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Methodology
- For the observed parameters of IMF, Magnetosheath and Magnetosphere and Magnetopause find the model predicted x-line locations.
- Find the distance of x-line from MMS, along the magnetopause, for different models.
- Look at the statistical distribution of distances (histogram etc.) for different models.
Qudsi (qudsira@bu.edu)
- Look at the instances when MMS observed a jet reversal while crossing the magnetopause.
\left< \Delta V_{L} \right> = \pm 70 km/s
RESULTS
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The maximum shear model:
The maximum exhaust velocity model
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B_z \gt 0
B_z \lt 0
DISCUSSIONS
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Discussions:
For negative z-component of IMF, reconnection energy and bisection field models both give very similar statistics.
For positive z-component, shear and bisection model seem to do the best job of predicting the expected x-line
Statistically, bisection field model seem to perform better than other models for different IMF and magnetopause conditions.
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Thank You!
Link to the presentation
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AGU- 2022
By Ramiz Qudsi
AGU- 2022
A comparative study of reconnection X-line predictions on dayside magnetopause of Earth. Magnetic reconnection is a fundamental plasma process of key importance to several fields. Reconnection at Earth’s magnetopause drives magnetospheric convection and provides mass and energy input into the magnetosphere/ionosphere system. Despite this importance, the factors governing the location of dayside magnetopause reconnection are not well understood. Though a few models can predict X-line locations reasonably well the underlying physics is still unresolved. In this study we present results from an intensive analysis of over 100 reconnection regions observed by MMS to determine what quantities are most strongly associated with the occurrence of dayside magnetopause reconnection. We also attempt to answer under what upstream conditions are global X-line models least reliable.
