We study the relationship between solar wind helium to hydrogen abundance ratio ( \mathrm { A } _ { \mathrm { He } } ) , \added solar wind speed ( v _ { \mathrm { sw } } ) , and sunspot number ( \mathrm { SSN } ) over solar cycles 23 and 24 .
This is the first full 22-year Hale cycle measured with the Wind spacecraft \replaced showing one complete rotation or cycle of the solar dipolecovering a full cycle of the solar dynamo with two polarity reversals .
While previous studies have established a strong correlation between \mathrm { A } _ { \mathrm { He } } and \mathrm { SSN } , \replaced here we show a consistent speed-dependent offset between the two quantitieswe show that the phase delay between \mathrm { A } _ { \mathrm { He } } and \mathrm { SSN } is a monotonic increasing function of v _ { \mathrm { sw } } .
Correcting for this lag , \mathrm { A } _ { \mathrm { He } } returns to the same \added value at a given \mathrm { SSN } over all rising and falling phases and across solar wind speeds . \added We infer that this speed-dependent lag is a consequence of the mechanism that depletes slow wind \mathrm { A } _ { \mathrm { He } } from its fast wind value during solar wind formation .