Possible solar cycle dependence of hydromagnetic waves in the earth's magnetosphere

The implications for hydromagnetic waves in the Earth's magnetosphere of recently published data on the solar cycle dependence of the annual average of the interplanetary magnetic field are discussed. We point out that, all other conditions remaining the same, a significant solar cycle dependence will occur in the annual average frequencies of hydromagnetic waves (band ∼ 30-50 mHz) in the Earth's dayside magnetosphere at L-values ∼ 4 to ∼ 7. (author)