SWIA measurements of the solar wind. At the highest altitudes (2,880 – 5,640 km), you can see the peaks at the correct energy/charge ratio for H+ and He++ in the free upstream solar wind. At intermediate altitudes (250 – 380 km), these peaks are not present, suggesting that the solar wind has not penetrated to these altitudes. However, the H+ peak shows up again at lower altitudes (160 – 210 km). (Courtesy Jasper Halekas/University of Iowa)
