We report the simultaneous observation of electron cyclotron harmonic (ECH) waves and mirror modes in the outer magnetosphere using NASA's Magnetospheric Multiscale data. The ion temperature anisotropy caused by the substorm injection can provide free energy to generate the mirror modes in the magnetosphere. Then the mirror modes modulate the electron distribution and form the loss cone distribution, which is responsible for the excitation of the ECH waves. Our study not only presents the mirror modes caused by mirror instability inside the Earth's magnetosphere but also discovers that the electron loss cone distribution modulating by mirror modes can generate ECH waves. Therefore, our study can provide new insight into the generation of mirror modes and ECH waves in the Earth's magnetosphere.

地球磁层,镜像模,电子回旋谐波