  In PYTHIA6 (PYTHIA8) once the transverse momentum $p_T$ of a generated
particle is randomly sampled, $p_x$ and $p_y$ are set on the circle with radius
of $p_T$ randomly. This may largely suppress the development of the final
hadronic state transverse momentum anisotropy from the initial state spatial
asymmetry. We modify PYTHIA6.4 by randomly setting $p_x$ and $p_y$ on the
circumference of an ellipse with the half major and minor axes being
$p_T(1+\delta_p)$ and $p_T(1-\delta_p)$, respectively. The modified PYTHIA6.4
is then employed to systematically study the charged particle transverse
momentum asymmetry in the minimum bias pp collisions at $\sqrt s$=0.9, 7, and
14 TeV. The ALICE data on the transverse sphericity as a function of charged
multiplicity, $<S_T>(N_{ch})$, are well reproduced with the modified PYTHIA6.4.
It is found that the predicted charged particle $v_2$ upper limit is a
measurable value, $\sim 0.12$, in the minimum bias pp collisions at $\sqrt s$=7
TeV. We suggest a systematic measurement for the particle transverse momentum
sphericity, eccentricity (ellipticity), and elliptic flow parameter.
