Detection of jets and associated toroidal fields in the solar tachocline

Tachocline toroidal fields are likely to exist in the form of narrow bands, at least during some phases of the solar cycle. Recent theoretical studies show that a narrow toroidal band in the solar tachocline can be held in equilibrium against its poleward slip due to the curvature stress by Coriolis forces from a prograde jet inside the band. Early attempts to detect convection-zone jets were made with the 7-month GONG data available at that time, but no clear evidence of jets was detected. We explore here long-term GONG data, in order to detect the amplitude, width and the latitude-location of jets that could exist in addition to background zonal flows. Using the latitudinal force-balance equation for toroidal bands in a typical solar tachocline, we first generate artificial helioseismic data that contain jets and we invert them in order to recover the jets. After this validation of the technique, we apply it to inversion of real data at different epochs.