Almost all papers on plasma mentioned that **plasma ions drag** on a particle is in the direction  is opposite to the velocity of the particle. But no one said anything about the other two components; are the other components zeroes? What about the velocity which is a vector and in any direction will always have three components which would mean three drags in opposite direction.
The Plasma drag ( Morfill 1980, Gruen et. al. 1984, Northop 1989,1990,1992) is given by 
 
 $F = - 2\sqrt{\pi}b^2 n_i m_i u^2 $

$n_i$ = plasma ions density, $m_i$= masss density, $b$ = radius of the particle and $u$=relative vel0city of the particle w.r.t plasma.

Since the velocity is spherical polar coordinates is:

$\dot{r}= \vec v$ = $r\hat{r}$ + $r\dot{\phi}\hat{\theta}$ + $r\dot{\phi}\sin{\theta}\hat{\phi}, $  \
$v^2$ = $r^2 + r^2{\dot{\theta}^2}+ r^2\dot{\phi}\sin^2{\theta}$

can the drag force be decomposed into:

$ F_r =- 2\sqrt{\pi}b^2 n_i m_i (r^2) $;

$ F_\theta =- 2\sqrt{\pi}b^2 n_i m_i (r^2{\dot{\theta}^2})$ ; 
 
$ F_\phi =- 2\sqrt{\pi}b^2 n_i m_i (r^2\dot{\phi}\sin^2{\theta}) ? $


If the particle is moving along the azimuthal direction 
is the total force equivalent to

$ F_\phi =- 2\sqrt{\pi}b^2 n_i m_i (r^2\dot{\phi}\sin^2{\theta}) ? $

 Supposing, the plasma is at the origin of a Spherical polar Frame and a particle is passing through it at some radial distance, at ang co-latitude angle (θ) = 45degree and azimulth angle (ϕ) =60degree. How would one find the drag force if one is interested in the effect along the components or let say one is interested in finding the path of the particle?