Lyman-alpha lines of hydrogenlike Ti21+ have been observed with an electron
-beam ion trap. The intensity ratio between Lyman-alpha (1), and -alpha (2)
was measured at electron energies of 10.6, 24.7, and 49.6 keV (2.12, 4.96,
and 9.96 in threshold units). The linear polarization of Lyman-alpha (1) w
as obtained by comparing the experimental intensity ratio at an observation
angle of 90 degrees with the total emission cross section ratio calculated
by a simple collisional radiative model. The present results are compared
with existing theoretical results.