If the midpoint of a chord of the ellipse \( \frac{x^{2}}{9}+\frac{y^{2}}{4}=1 \) is \( \left(\sqrt{2}, \frac{4}{3}\right) \), and the length of the chord is \( \frac{2\sqrt{a}}{3} \), then \( \alpha \) is:
\( 26 \)
\( 18 \)
\( 20 \)
\( 22 \)