You see that files with name ‘Core’ is created under your account.
These core files start taking the space on your server.
Core dump consists of the recorded state of the working memory.
Generally when the program/script/application has terminated abnormally these files created.
You can delete those files,but a permanent fix to the problem is as follows:
1) Ssh server as root
2) Edit /etc/init.d/httpd and add ulimit -c 0 below ulimit -n
3) Save and exit from file and restart Apache service.