As the central engine of gamma-ray bursts (GRBs), a nascent magnetar can release its rotational energy by magnetic dipole radiation. This energy is injected into the outflow of the GRB jet. With the rapid evolution of the magnetic inclination angle, the perpendicular component of the magnetar’s surface magnetic field decreases rapidly. The energy loss rate of the magnetar is characterized by two different timescales. This peculiar two-stage energy injection model will affect the shape of the X-ray afterglow light curve. It is shown that a new shallow decay phase will emerge following the initial shallow decay phase. As a result, there could be two plateaus in the X-ray light curve. The effects of various physical parameters on the light curves are studied in detail. It is found that the observed afterglows of GRB 161217A and GRB 190114A, both having two plateaus in the light curve, can be well fitted in our framework.

作为伽马射线暴 (GRB) 的核心引擎，新生的磁星可以通过磁偶极辐射释放其旋转能量。这种能量被注入到 GRB 射流的外流中。随着磁倾角的快速演化，磁星表面磁场的垂直分量迅速减小。磁星的能量损失率具有两个不同的时间尺度。这种奇特的两级能量注入模型会影响X射线余辉光曲线的形状。结果表明，在最初的浅衰减阶段之后将出现一个新的浅衰减阶段。因此，X 射线光变曲线可能有两个平台。详细研究了各种物理参数对光变曲线的影响。发现观察到的GRB 161217A和GRB 190114A的余辉，