tokens: Spacecraft in L1 and L2 shall be considered to experience the same mean and range of plasma parameters in the solar wind as at the Earth . NOTE Because the solar wind flows through the near - Earth interplanetary medium with negligible modification ( unless it encounters the bow shock ) , the mean and range of plasma density and temperature can be considered spatially uniform in the vicinity of 1AU . However , variations in plasma at the Earth are seen at L1 and L2 between approximately 30 and 90 minutes earlier or later , respectively .