In this work, we shall demonstrate that usual expression of time-averaged stored energy density (TASED) for disperisve medium is invalid, which is mainly attributed to the fact that there exist mathematical errors in derivation of this expression. Noting connection between TASED and time-averaged Poynting vector (TAPV) and the case that TAPV of a pulse is the sum of TAPVs of its components, similarly, it is verified that TASED of a pulse in disperisve medium can be taken as the sum of TASEDs of all its components. This work may be helpful to gain a better understand of stored energy of electromagnetic wave in material media.

中文翻译：

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电磁波在分散介质中的存储能量密度

在这项工作中，我们将证明分散介质的时间平均储能密度（TASED）的通常表达式是无效的，这主要归因于该表达式的推导存在数学错误。注意到TASED和时间平均Poynting向量（TAPV）之间的联系以及脉冲的TAPV是其分量的TAPVs之和的情况，类似地，验证了可以将脉冲在分散介质中的TASED取作TASED的所有组成部分。这项工作可能有助于更好地了解电磁波在材料介质中的存储能量。