pyrfu.pyrf.calc_dng module#
- pyrfu.pyrf.calc_dng.calc_dng(p_xyz)[source]#
Computes agyrotropy coefficient as in [15]
\[D_{ng} = \frac{\sqrt{8 (P_{12}^2 + P_{13}^2 + P_{23}^2)}} {P_\parallel + 2 P_\perp}\]- Parameters:
p_xyz (xarray.DataArray) – Time series of the pressure tensor
- Returns:
d_ng – Time series of the agyrotropy coefficient of the specie.
- Return type:
References
[15]Aunai, N., M. Hesse, and M. Kuznetsova (2013), Electron nongyrotropy in the context of collisionless magnetic reconnection, Phys. Plasmas, 20(6), 092903, doi: https://doi.org/10.1063/1.4820953.
Examples
>>> from pyrfu import mms, pyrf
Time interval
>>> tint = ["2019-09-14T07:54:00.000","2019-09-14T08:11:00.000"]
Spacecraft index
>>> ic = 1
Load magnetic field and electron pressure tensor
>>> b_xyz = mms.get_data("b_gse_fgm_srvy_l2", tint, 1) >>> p_xyz_e = mms.get_data("pe_gse_fpi_fast_l2", tint, 1)
Rotate electron pressure tensor to field aligned coordinates
>>> p_fac_e_pp = mms.rotate_tensor(p_xyz_e, "fac", b_xyz, "pp")
Compute agyrotropy coefficient
>>> d_ng_e = pyrf.calc_dng(p_fac_e_pp)