'There ' in an adverb introducing the subject of a sentence.
Usually when used with verb to be the subject the subject takes the indefinite article or just the plural of the subject if using the plural form of verb to be (there are ).
There are cases nevertheless where you could use 'the' in this context as in the idiom :
There is the rub ( meaning here is the difficulty or the problem ).
There must be other occasions ,where you could use a definite article here ,specially in literary works where you could say for example :
There is the love ,that will be ready to embrace you .
Here it means there is that very special love ,it is pointing out and specifying ,thus using the article 'the' .