.. _vexelsbible:

=============
VEX/ELS bible
=============

The ELS Bible is for the instrument description prepared for data analysis.

VEX/ELS bible is provided from MSSL, and you can download from :file:`../../../doc/VenusExpressELSDataAnalysisSummary2.pdf`.

.. todo::

        To make the link active.

Package :mod:`irfpy.vels.bible` contains the implementation.

Error in ELS bible
==================

PSD calculation
-----------------
PSD calculation in equation 10 contains a small error.
According to the definition in the bible, earray is in ``eV`` and E is ``J/eV``.
Thus, :math:`earray \times E` should be in ``J`` = ``kg m2 / s2``.
To use the unit of ``cm``, the term should be changed to be
:math:`(1e2)^2 \times earray \times E`.
So the correct expressions is :math:`PSD [cm^{-6} s^3] = \frac{raw \times m_e^2}
{GF \times accutime \times 2 \times (1e4 \times earray \times E)^2 \times A_A}`

The error has been corrected for the implementation of :func:`irfpy.vels.bible.flux.raw2psd`.