Correction to: Observation of the Solar Corona Using Radio Scintillation with the Akatsuki Spacecraft: Difference Between Fast and Slow Wind

Correction to: Solar Physics (2022) 297: 34 https://doi.org/10.1007/s11207-022-01968-9

We wish to correct Equation 2. This formula is valid when the radio source is located at infinitely large distances, such as radio-astronomical measurements. In our case, the distance between the source and the observer (ground antenna) is relatively short, and the following formula should be used (Yakovlev, 2002):

$$ F_{\mathrm{diff}} \left( k \right) = 4 \sin^{2} \left( \frac{L_{1} L_{2}}{L_{1} + L_{2}} k^{2} \frac{\lambda}{4 \pi} \right)^{2}, $$

(2)

where $L_{1}$ is the distance between the ground antenna and the point of closest approach, and $L_{2}$ is the distance between the point of closest approach and the source of radio waves (spacecraft). In this formula, the density spectrum is defined at the closest point (thin-screen model), as in the original manuscript. The definition of the Fresnel wavenumber, which appears in the text, in Section 3.1, is also changed to

$$k_{\mathrm{F}} = \frac{\pi}{\left( \lambda {L_{1} L_{2}} / {\left( L_{1} + L_{2} \right)} \right)^{1/2}}. $$

Accordingly, the results of the parameter fitting were changed (see Figures 6, 7, 8, and 12b). The conclusions are not changed.

Figure 6

Observed spectra (black) and model fits (orange) for the observations on the western side (upper row) and the eastern side (lower row) of the Sun. The heliocentric distance is indicated above each panel and decreases from left to right. The obtained parameter values with fitting errors are also given in the panels.

Figure 7

Radial distributions of the estimated parameters: ($\mathbf{a}$) solar-wind velocity, ($\mathbf{b}$) power-law exponent, ($\mathbf{c}$) axial ratio, and ($\mathbf{d}$) inner scale. Filled black circles and blue crosses indicate observations on the western and eastern sides, respectively. The open circles in ($\mathbf{a}$) indicate the solar-wind velocities in closed-loop regions obtained by Akatsuki’s radio-occultation observations in 2011 (Imamura et al., 2014); a measurement that is thought to reflect the fast wind was excluded.

Figure 8

Comparison between the observed inner scales and theoretical models. The dashed line represents the inertial-length model and the solid line represents the gyroradius model. Filled black circles and blue crosses indicate observations on the western and eastern sides, respectively.

Figure 12

Radial distributions of ($\mathbf{a}$) the electron column density amplitude and ($\mathbf{b}$) the relative-density amplitude of the detected wave packets. Circles show observations on the western side of the Sun and triangles show observations on the eastern side. The color represents the period of each wave packet. Arrows indicate the observations that probed the fast solar wind originating from coronal holes.