  In this paper, we present a linearly implicit energy-preserving scheme for
the Camassa-Holm equation by using the multiple scalar auxiliary variables
approach, which is first developed to construct efficient and robust energy
stable schemes for gradient systems. The Camassa-Holm equation is first
reformulated into an equivalent system by utilizing the multiple scalar
auxiliary variables approach, which inherits a modified energy. Then, the
system is discretized in space aided by the standard Fourier pseudo-spectral
method and a semi-discrete system is obtained, which is proven to preserve a
semi-discrete modified energy. Subsequently, the linearized Crank-Nicolson
method is applied for the resulting semi-discrete system to arrive at a fully
discrete scheme. The main feature of the new scheme is to form a linear system
with a constant coefficient matrix at each time step and produce numerical
solutions along which the modified energy is precisely conserved, as is the
case with the analytical solution. Several numerical results are addressed to
confirm accuracy and efficiency of the proposed scheme.
