Effects of Heavier Ions (O $^{+}$ and O $^{-})$ on the Characteristics of Ion-Acoustic Double Layers in Comet 1P/Halley

The effects of pair ions (O
$^{+}$
& O
$^{-}$
) on the existence and propagation characteristics of ion-acoustic double layers (IADLs) are studied in a six-component cometary plasma, consisting of two hot and one colder components of electrons, hot ions, and a pair of heavier ions. One of the hotter and the colder component of electrons, together with the lighter hydrogen ions, is modeled by kappa distributions. The second, hotter component of electron is modeled by a
$q$
-nonextensive distribution. Both the Korteweg–deVries (KdV) and the modified KdV (mKdV) equations are derived for the system and its solutions are studied for parameters pertinent to comet Halley. It is observed that the strength of the DL profile and depth of the Sagdeev potential significantly depend on the heavier ion densities. The variations of both the quadratic and cubic nonlinearities with densities of the heavier ions are also studied. Our results can be expected to contribute to an understanding of DLs in cometary plasmas.