  The relative abundance of alpha particles with respect to proton, usually
expressed as $A_{He}$ = ($n_\alpha/n_p$)*100, is known to respond to solar
activity although changes in its behaviour in the last four solar cycles are
not known. In this letter, by systematically analysing inter-calibrated
$A_{He}$ data obtained from the first Lagrangian point of the Sun-Earth system,
we show that $A_{He}$ variations are distinctively different in solar cycle 24
as compared to the last three cycles. The frequency of $A_{He}$ = 2-3% events
is significantly higher in slow/intermediate solar winds in cycle 24 as opposed
to the dominance of the typical $A_{He}$ = 4-5% events in the previous three
cycles. Further, the occurrence of $A_{He}$ $\geq$ 10% events is significantly
reduced in cycle 24. Not only that, the changes in delay of $A_{He}$ with
respect to peak sunspot numbers are less sensitive to changes in solar wind
velocity in cycle 24. The investigation suggests that the coronal magnetic
field configuration started undergoing systematic changes starting from cycle
23 and this altered magnetic field configuration affected the way helium got
processed and depleted in the solar atmosphere.
