pyrfu.pyrf.calc_ag module#
- pyrfu.pyrf.calc_ag.calc_ag(p_xyz)[source]#
Computes agyrotropy coefficient as in [16]
\[AG^{1/3} = \frac{|\operatorname[det]{\mathbf{P}} - \operatorname[det]{\mathbf{P}}|} {\operatorname[det]{\mathbf{P}} + \operatorname[det]{\mathbf{P}}}\]- Parameters:
p_xyz (xarray.DataArray) – Time series of the pressure tensor
- Returns:
agyrotropy – Time series of the agyrotropy coefficient of the specie.
- Return type:
References
[16]H. Che, C. Schiff, G. Le, J. C. Dorelli, B. L. Giles, and T. E. Moore (2018), Quantifying the effect of non-Larmor motion of electrons on the pres- sure tensor, Phys. Plasmas 25(3), 032101, doi: https://doi.org/10.1063/1.5016853.
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
>>> ag_e, ag_cr_e = pyrf.calc_ag(p_fac_e_pp)