A method and a control sequence determination device for determining a magnetic resonance system activation sequence are described. The magnetic resonance system activation sequence includes a multichannel pulse train with a plurality of individual HF pulse trains to be emitted in a parallel manner by the magnetic resonance system by way of different independent high-frequency transmit channels. In this process, a multichannel pulse train is calculated with a predefined target magnetization using an HF pulse optimization method, with optimization taking place with respect to a setpoint deviation of an HF local exposure value from an HF global exposure value. A method for operating a magnetic resonance system and a magnetic resonance system with the control sequence determination device are also described.