Ramiz Qudsi
From state of caffeination to citation!
A comparative study of reconnection
X-line predictions on dayside magnetopause of Earth
Ramiz A. Qudsi, Brian Walsh, J. Broll
Boston University, Los Alamos National Lab
*(qudsira@bu.edu)
1, * 1 2
1 2
Qudsi Center for Space Physics, BU qudsira@bu.edu
Outline:
- Region of interest
- Location of x-line
- Different models
- Data
- Results
- Discussions
Qudsi Center for Space Physics, BU qudsira@bu.edu
The BASICS
Qudsi Center for Space Physics, BU qudsira@bu.edu
Source: NASA
Qudsi Center for Space Physics, BU qudsira@bu.edu
Region of interest:
[Broll et al., 2017]
Source: wikipedia
Qudsi Center for Space Physics, BU qudsira@bu.edu
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]
Qudsi Center for Space Physics, BU qudsira@bu.edu
Magnetic shear:
\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:
Reconnection field energy:
E \propto \left(B_{\rm sh}^2 \times B_{\rm msp}^2\right)
Exhaust speed:
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
Qudsi Center for Space Physics, BU qudsira@bu.edu
DATA
Qudsi Center for Space Physics, BU qudsira@bu.edu
Data:
Solar
Wind
T-96 and IGRF Model
OMNI
Cooling-2001 Model
Magnetosheath
Magnetopause
Shue-1998 Model
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
Qudsi Center for Space Physics, BU qudsira@bu.edu
Methodology
Qudsi Center for Space Physics, BU qudsira@bu.edu
- Look at the instances when MMS observed a jet reversal while crossing the magnetopause.
Magnetosheath
Magnetosphere
[Broll et al., 2017]
Qudsi Center for Space Physics, BU qudsira@bu.edu
Methodology
Qudsi Center for Space Physics, BU qudsira@bu.edu
- Look at the instances when MMS observed a jet reversal while crossing the magnetopause.
- For the given parameters of IMF, Magnetosheath and Magnetosphere and Magnetopause find the predicted x-line locations.
- Find the distance of x-line from MMS, along the magenosheath field, for different models.
- Look at the statistical distribution of distances (histogram etc.) for different models.
RESULTS
Qudsi Center for Space Physics, BU qudsira@bu.edu
The maximum shear model
The maximum exhaust velocity model
Qudsi Center for Space Physics, BU qudsira@bu.edu
DISCUSSIONS
Qudsi Center for Space Physics, BU qudsira@bu.edu
Discussions:
Most model fail when the z-component of magnetic field is positive. Though bisection model seems to perform better than other 3.
The spread in the histogram of shear model appear to be maximum.
Need a lot more reconnection events for a better understanding.
As expected, different models predict different location of x-lines for the same dataset.
Qudsi Center for Space Physics, BU qudsira@bu.edu
Thank You!
Qudsi Center for Space Physics, BU qudsira@bu.edu
Link to the presentation
MMS Reconnection Meeting
By Ramiz Qudsi
MMS Reconnection Meeting
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.
