When the solar plexus (the Sun of our being) is overactive or inflated one can become domineering, aggressive, angry and overcritical of oneself and others. When it is underactive one can be indecisive, passive, timid and lacking in self control. 
This center of our beings is an important interface between our emotions and action through one's heart. Anger is a difficult emotion that often gets stuck when it gets here, one becomes trapped in it, not knowning how to utilize it as a motivation to go further.
This meditation will assist a feeling of strength and calm through your solar center, as once it is in balance you will have an easier process of emotion to action with the healthy fire of your divine willpower.