In this paper, we propose a scheme to generate tunable multi-color attosecond
coherent X-ray radiation for future light source applications. This scheme uses
an energy chirped electron beam, a laser modulators, a laser chirper and two
bunch compressors to generate a multi-spike prebunched kilo-Ampere current
electron beam from a few tens Ampere electron beam out of a linac. Such an
electron beam transports through a series of undulator radiators and bunch
compressors to generate multi-color coherent X-ray radiation. As an
illustration, we present an example to generate two attosecond pulses with
2.2 nm and 3 nm coherent X-ray radiation wavelength and more than 200 MW
peak power using a 30 Ampere 200 nm laser seeded electron beam