IMF Reconstruction using Machine Learning:

Proof of Concept

Ramiz A. Qudsi

qudsira@bu.edu

(https://qudsiramiz.github.io)

https://slides.com/qudsi/magnetore_bu

Multiscale nature of IMF

Coleman (ApJ, 1968)

Bale et al. (Natur, 2019)

Competing Theories of Turbulence

Critical effects of magnetic structure on plasma dynamics:

Propagation of energetic particles
3D context of kinetic processes like magnetic reconnection

How do we get the full 3D structure of magnetic field?

Put a magnetometer at every point in space

Launch a constellation of spacecraft with magnetometers on them

Compute values at rest of the points by interpolation

Conventional interpolation are not best suited

Gaussian Processes in Machine Learning

Hub

Spacecrafts

$$d_i$$

Some relevant scales:

d_i \mathrm{(1AU)} \sim 100 ~\mathrm{km} \\ V_{sw} \sim 500 ~\mathrm{km/sec} \\ X_{sim} \mathrm{(box size)} \sim 40 d_i\\ \hspace{3.1cm}\sim 4\times 10^3 \mathrm{km}\\ d_{spc} \sim [1, 11]~d_i\\ \hspace{1.2cm}\sim \mathrm{ [10^2, 10^3]~ km} \\ f[min,max] \sim V_{sw}/(2\times d_{spc, max, min}) \\ \hspace{0.8cm}\sim [0.25, 2.5]~\mathrm{Hz}\\ \nu (\mathrm{sampling~rate}) \sim 40 \mathrm{Hz}\\ \mathrm{(just~because~of~box~size~and~stuff)}\\ \mathrm{time~to~move~across~the~simulation~box} \sim 10 ~\mathrm{sec}