Generation of extremely short attosecond pulses is one of the key fields of modern optics [1-3]. Such pulses enable control over the electron wave packets dynamics at the smallest time scales [1, 4]. Recently, different methods of generation of strong half-cycle attosecond pulses in XUV but also in the optical range have been proposed [2, 3]. Such pulses contain a half-wave of single optical polarity followed by a weak and long decaying tail of opposite polarity. Such half-cycle pulses can be thus considered as 'quasi-unipolar' because of having nonzero electric pulse area S_E = ∫ E(t)dt in their most intense part. To date, interaction of such quasi-unipolar pulses with matter for the pulse duration comparable to the timescale of electron movement in atom is poorly understood.