Issue on copy Internal Table using field-symbol

Hi Experts,

I am trying to copy Internal table by use of field-symbol.

I wrote code like below.

DATA: itab1 TYPE STANDARD TABLE OF t100,  

          itab2 TYPE STANDARD TABLE OF t100.

FIELD-SYMBOLS: <fs_1> TYPE ANY TABLE,

                            <fs_2> TYPE ANY TABLE.

ASSIGN itab1 TO <fs_1>.

SELECT * FROM t001

         INTO TABLE <fs_1>

         UP TO 10 ROWS.

ASSIGN itab2 TO <fs_2>.

<fs_2> = <fs_1>.

DATA: v_lines TYPE i.

v_lines = LINES( <fs_2> ).

WRITE: v_lines.

My Problem is : While i am executing this program its going for dump and shows that : " The Itab use to hold the record must as wide as the db table from where you fetch the data records.

So How i increase the  size of <fs_1> field symbol , so that it will keep the records from T001 Table.

Regards,

Ajit