H- continuum
============

ExoJAX supports the H- continuum. The H- continuum is an important
continuum opacity under high-temperature hydrogen atmospheres, such as
those of ultra-hot Jupiters. Currently, the model by John (1988) is
adopted.
`OpaHminus <../exojax/exojax.spec.html#exojax.spec.opacont.OpaHminus>`__
class is available.

.. code:: ipython3

    from exojax.spec.opacont import OpaHminus
    from exojax.utils.grids import wavenumber_grid
    N=10000
    nu_grid, wav, res = wavenumber_grid(9000.0, 18000.0, N, xsmode="premodit", unit="AA")
    opa = OpaHminus(nu_grid)
        


.. parsed-literal::

    xsmode =  premodit
    xsmode assumes ESLOG in wavenumber space: xsmode=premodit
    ======================================================================
    The wavenumber grid should be in ascending order.
    The users can specify the order of the wavelength grid by themselves.
    Your wavelength grid is in ***  descending  *** order
    ======================================================================


.. parsed-literal::

    /home/kawahara/exojax/src/exojax/spec/unitconvert.py:63: UserWarning: Both input wavelength and output wavenumber are in ascending order.
      warnings.warn(
    /home/kawahara/exojax/src/exojax/utils/grids.py:144: UserWarning: Resolution may be too small. R=14425.507713848727
      warnings.warn("Resolution may be too small. R=" + str(resolution), UserWarning)


The logarithmic absorption coefficient can be calculated using
``opa.logahminus_matrix``. For an example with WASP-33b, please refer to
`this
resource <https://github.com/HajimeKawahara/exojax/issues/94#issuecomment-1034576068>`__.

.. code:: ipython3

    import jax.numpy as jnp
    Tarr = jnp.array([2500.0,3000.0, 3500])
    a = opa.logahminus_matrix(Tarr, 1.0, 1.0)

.. code:: ipython3

    import matplotlib.pyplot as plt
    
    plt.style.use("bmh")
    for i in range(0, len(Tarr)):
        plt.plot(wav, a[i, :], lw=1, label=str(int(Tarr[i])) + " K")
    plt.xlabel("wavelength ($\\AA$)")
    plt.ylabel("absorption coefficient ($\mathrm{cm}^{-1}$)")
    plt.legend()
    plt.show()



.. image:: Hminus_files/Hminus_5_0.png