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Magnetic Wind From a Massive White Dwarf Merger: Convergence of Resultsby@magnetosphere

Magnetic Wind From a Massive White Dwarf Merger: Convergence of Results

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This paper explores the observation properties of massive white dwarf merger remnants with a strong magnetic field, a fast spin, and intense mass loss.
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This paper is available on arxiv under CC 4.0 license.

Authors:

(1) Yici Zhong, Department of Physics, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan;

(2) Kazumi Kashiyama, Research Center for the Early Universe, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan and Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU,WPI), The University of Tokyo, Chiba 277-8582, Japan;

(3) Shinsuke Takasao, Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan;

(4) Toshikazu Shigeyama, Research Center for the Early Universe (RESCEU), School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan and Department of Astronomy, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan;

(5) Kotaro Fujisawa, Research Center for the Early Universe (RESCEU), School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan and Department of Liberal Arts, Tokyo University of Technology, Ota-ku, Tokyo 144-0051, Japan.

Abstract and Intro

Setup

Result

Summary and Discussion


Appendix

A. Dual Energy Formalism

B. Convergence of Results

C. Change of the Mass Loss Rate in MHD Regime

References

B. CONVERGENCE OF RESULTS

The convergence of our rotating magnetic wind solutions against both mesh resolution and the size of wind launching

region have been confirmed. We show the results for our fiducial model (B1.5e6Ω0.23) in Fig. 5. In the top panel we

increase the spatial resolution for 4 times both along the radial and latitudinal direction, while in the bottom panel we

change the thickness of wind launching region from D = 0.6 R∗ (fiducial value we are using, corresponding to 9 cells)

to D = 0.3 R∗ (which corresponds to 5 cells). We check the time evolution of the spindown torque T for both changes,

and zoom into the first few eruptive peaks to show the difference clearly. We find that the time-averaged value as well

as the power-law trend converge with respect to both the spatial resolution and the size of the wind launching region,

but the time variability vary. This is due to the fact that the reconnections in our simulations are mainly modulated

by numerical resistivities.


Figure 5. Time evolution of spin-down torque before and after (a) increasing resolution (b) decreasing the size of wind launching region in our fiducial case (B1.5e6Ω0.23).