New Hampshire voters remain split on whether Clinton is fit to be president, 48 percent saying she is and 46 saying she is not. | AP Photo Poll: Clinton leads Trump by 15 in New Hampshire

Hillary Clinton has opened up a 15-point advantage over Donald Trump in the battleground state of New Hampshire, according to the results of the latest WBUR poll released Thursday, which also found the state’s Democratic Gov. Maggie Hassan with a double-digit lead over incumbent Republican Sen. Kelly Ayotte.

The survey, conducted in the days immediately following the Democratic National Convention, found Clinton with 47 percent support among likely voters. Trump has the backing of 32 percent of voters, while Libertarian nominee Gary Johnson finished a distant third with 8 percent and Green Party candidate Jill Stein took 3 percent. Another 2 percent indicated support for another candidate, while 7 percent did not know or refused to answer.

Clinton held a much narrower two-point edge over Trump in a WMUR/University of New Hampshire poll taken before the convention. National polls taken after both conventions showed Clinton erasing any bounce Trump gained from the previous week when he briefly surged following the Republican National Convention.

Likely New Hampshire voters are split on whether Clinton is fit to be president, with 48 percent saying she is and 46 percent responding that she is not, with 6 percent undecided.

But they are far more certain about Trump, with more than six in 10 — 63 percent — responding that the Republican presidential nominee is not fit for office and 31 percent indicating that he is.

Clinton’s image has also improved in the state. While only 35 percent said they had a favorable image of Clinton in May (compared with 58 percent unfavorable), 45 percent indicated after the convention that they had a positive view of her, as well as 45 percent who said they saw her unfavorably. Trump’s image remained largely consistent from the previous poll, with 29 percent holding a favorable view of him (33 percent in May) and 60 percent unfavorable (58 percent in May).

Approval of the Democratic ticket and disdain for the Republican candidates extends to the vice presidential candidates as well. While Virginia Sen. Tim Kaine has a net-positive approval rating of +14 points (33 percent favorable to 19 percent unfavorable), Indiana Gov. Mike Pence drew a net-negative approval rating of -7 points (24 percent favorable to 31 percent unfavorable). Meanwhile about half of the likely voters surveyed have either never heard of the running mates or have not yet made up their minds about them.

Voters overwhelmingly rejected the notion that Clinton should be sent to prison over her handling of classified materials through a private server while secretary of state, a frequent subject at the Republican convention last month in Cleveland and the resulting “lock her up” chant a common refrain at Trump rallies. While 29 percent said Clinton should go to prison, 60 percent said she should not, and 11 percent said they did not know.

As far as who had a better convention, 56 percent said Clinton emerged from Philadelphia “a little” or “much stronger,” while 39 percent said Trump did the same after Cleveland. While 23 percent suggested that the DNC weakened Clinton’s candidacy to some degree, 38 percent said the same of Trump at the RNC.

In the state’s contentious Senate race, Gov. Maggie Hassan leads Sen. Kelly Ayotte by 10 points—50 percent to 40 percent.

While voters are divided on whether their lives are any better or worse in the state over the last few years, Hassan’s image among likely voters is significantly better than Ayotte’s. Overall, 42 percent said they have a favorable opinion of the junior senator first elected in 2010, with 38 percent unfavorable, margins largely unchanged from WBUR’s May survey. Approximately half, or 50 percent, of likely voters say they view their governor favorably, while 32 percent do not, in line with the previous poll.

Trump insists that he is doing well in New Hampshire, a state he won handily during the Republican primary.

“New Hampshire is one of my favorite places,” he told the Washington Post in an interview Tuesday. “You have a Kelly Ayotte who doesn’t want to talk about Trump, but I’m beating her in the polls by a lot. You tell me. Are these people that should be representing us, OK? You tell me.

"I don’t know Kelly Ayotte," he continued. "I know she’s given me no support — zero support — and yet I’m leading her in the polls. I’m doing very well in New Hampshire. We need loyal people in this country. We need fighters in this country. We don’t need weak people. We have enough of them. We need fighters in this country. But Kelly Ayotte has given me zero support, and I’m doing great in New Hampshire.”

The MassINC Polling Group conducted the poll from July 29-Aug. 1, surveying 609 likely voters via landlines and cellphones. The overall margin of error is plus or minus 4 percentage points.