Space charge limit for light sources

With the adoption of multi-bend achromat lattices and the aim for diffraction limit, the state-of-the-art light sources are approaching a point where their emittance becomes so small that the effects of space charge can no longer be ignored. Space charge produces a significant betatron tune spread that affects many aspects of beam dynamics: single particle dynamics to collective beam stability. But most importantly, space charge imposes a fundamental limit to the ultimate beam brightness that can be achieved in a synchrotron light source. We demonstrate that the only way to increase the beam brightness and therefore the photon brilliance further is to opt for a higher beam energy.