The Global Oscillations at Low Frequency: New Generation instrument (GOLF-NG), the successor of GOLF aboard SoHO, is devoted to the study the dynamics of the solar radiative zone thanks to the detection of solar gravity modes and low-frequency acoustic modes. This instrument built under a French-Spanish collaboration, is based on the Doppler velocity method using a 15 points resonant scattering spectrometer working on the D1 sodium line and will be placed in Tenerife. The observations of the space version called DynaMICS (for Dynamics and Magnetism of the Innner Core of the Sun) will enable us to improve our knowledge of the radiative zone, especially the solar core and the influence of the Sun on our planet by the determination of the origin of the magnetic activities. The investigation of the sodium line will also provide interesting information on the atmosphere of the Sun, between the photosphere and the chromosphere.